[{"data":1,"prerenderedAt":3063},["ShallowReactive",2],{"doc-\u002Fhow-to\u002Fhow-to-filter-a-list-in-python":3},{"id":4,"title":5,"body":6,"description":3056,"extension":3057,"meta":3058,"navigation":283,"path":3059,"seo":3060,"stem":3061,"__hash__":3062},"content\u002Fhow-to\u002Fhow-to-filter-a-list-in-python.md","How to Filter a List in Python",{"type":7,"value":8,"toc":3013},"minimark",[9,13,17,20,40,52,57,184,187,191,194,205,212,215,308,311,350,359,363,366,369,398,401,421,424,507,509,531,536,539,567,574,578,581,585,705,707,734,741,745,853,855,880,887,893,898,901,914,917,1054,1056,1076,1083,1092,1099,1188,1191,1234,1244,1248,1251,1343,1345,1378,1386,1389,1407,1413,1418,1494,1496,1521,1524,1528,1531,1534,1723,1725,1796,1800,1810,1817,1821,1828,1971,1977,1983,2149,2151,2188,2195,2199,2202,2206,2209,2296,2306,2312,2315,2330,2333,2406,2408,2425,2432,2435,2511,2513,2533,2536,2565,2569,2572,2575,2644,2646,2667,2678,2682,2685,2688,2785,2788,2870,2877,2881,2887,2898,2904,2915,2918,2929,2933,2937,2940,2947,2950,2954,2957,2964,2973,2977,3009],[10,11,5],"h1",{"id":12},"how-to-filter-a-list-in-python",[14,15,16],"p",{},"Filtering a list means keeping only the items that match a rule.",[14,18,19],{},"For example, you might want to:",[21,22,23,27,30,33],"ul",{},[24,25,26],"li",{},"keep only even numbers",[24,28,29],{},"keep only names longer than 4 letters",[24,31,32],{},"remove empty strings",[24,34,35,36],{},"keep only dictionaries where ",[37,38,39],"code",{},"age >= 18",[14,41,42,43,47,48,51],{},"In Python, the most common way to do this is with a ",[44,45,46],"strong",{},"list comprehension",". You can also use the built-in ",[37,49,50],{},"filter()"," function.",[53,54,56],"h2",{"id":55},"quick-answer","Quick answer",[58,59,64],"pre",{"className":60,"code":61,"language":62,"meta":63,"style":63},"language-python shiki shiki-themes material-theme-lighter github-light github-dark","numbers = [1, 2, 3, 4, 5, 6]\neven_numbers = [n for n in numbers if n % 2 == 0]\nprint(even_numbers)\n# Output: [2, 4, 6]\n","python","",[37,65,66,116,160,177],{"__ignoreMap":63},[67,68,71,75,79,83,87,90,93,95,98,100,103,105,108,110,113],"span",{"class":69,"line":70},"line",1,[67,72,74],{"class":73},"su5hD","numbers ",[67,76,78],{"class":77},"smGrS","=",[67,80,82],{"class":81},"sP7_E"," [",[67,84,86],{"class":85},"srdBf","1",[67,88,89],{"class":81},",",[67,91,92],{"class":85}," 2",[67,94,89],{"class":81},[67,96,97],{"class":85}," 3",[67,99,89],{"class":81},[67,101,102],{"class":85}," 4",[67,104,89],{"class":81},[67,106,107],{"class":85}," 5",[67,109,89],{"class":81},[67,111,112],{"class":85}," 6",[67,114,115],{"class":81},"]\n",[67,117,119,122,124,126,129,133,136,139,142,145,147,150,152,155,158],{"class":69,"line":118},2,[67,120,121],{"class":73},"even_numbers ",[67,123,78],{"class":77},[67,125,82],{"class":81},[67,127,128],{"class":73},"n ",[67,130,132],{"class":131},"sVHd0","for",[67,134,135],{"class":73}," n ",[67,137,138],{"class":131},"in",[67,140,141],{"class":73}," numbers ",[67,143,144],{"class":131},"if",[67,146,135],{"class":73},[67,148,149],{"class":77},"%",[67,151,92],{"class":85},[67,153,154],{"class":77}," ==",[67,156,157],{"class":85}," 0",[67,159,115],{"class":81},[67,161,163,167,170,174],{"class":69,"line":162},3,[67,164,166],{"class":165},"sptTA","print",[67,168,169],{"class":81},"(",[67,171,173],{"class":172},"slqww","even_numbers",[67,175,176],{"class":81},")\n",[67,178,180],{"class":69,"line":179},4,[67,181,183],{"class":182},"sutJx","# Output: [2, 4, 6]\n",[14,185,186],{},"Use a list comprehension when you want to build a new list by keeping only items that match a condition.",[53,188,190],{"id":189},"what-filtering-a-list-means","What filtering a list means",[14,192,193],{},"Filtering means:",[21,195,196,199,202],{},[24,197,198],{},"keeping some items",[24,200,201],{},"leaving out other items",[24,203,204],{},"creating a new list based on a condition",[14,206,207,208,211],{},"For example, if you only want numbers greater than ",[37,209,210],{},"10",", you check each item and keep the ones that match.",[14,213,214],{},"In most cases, the original list stays unchanged.",[58,216,218],{"className":60,"code":217,"language":62,"meta":63,"style":63},"numbers = [5, 12, 8, 20]\nfiltered = [n for n in numbers if n > 10]\n\nprint(numbers)\nprint(filtered)\n",[37,219,220,248,279,285,296],{"__ignoreMap":63},[67,221,222,224,226,228,231,233,236,238,241,243,246],{"class":69,"line":70},[67,223,74],{"class":73},[67,225,78],{"class":77},[67,227,82],{"class":81},[67,229,230],{"class":85},"5",[67,232,89],{"class":81},[67,234,235],{"class":85}," 12",[67,237,89],{"class":81},[67,239,240],{"class":85}," 8",[67,242,89],{"class":81},[67,244,245],{"class":85}," 20",[67,247,115],{"class":81},[67,249,250,253,255,257,259,261,263,265,267,269,271,274,277],{"class":69,"line":118},[67,251,252],{"class":73},"filtered ",[67,254,78],{"class":77},[67,256,82],{"class":81},[67,258,128],{"class":73},[67,260,132],{"class":131},[67,262,135],{"class":73},[67,264,138],{"class":131},[67,266,141],{"class":73},[67,268,144],{"class":131},[67,270,135],{"class":73},[67,272,273],{"class":77},">",[67,275,276],{"class":85}," 10",[67,278,115],{"class":81},[67,280,281],{"class":69,"line":162},[67,282,284],{"emptyLinePlaceholder":283},true,"\n",[67,286,287,289,291,294],{"class":69,"line":179},[67,288,166],{"class":165},[67,290,169],{"class":81},[67,292,293],{"class":172},"numbers",[67,295,176],{"class":81},[67,297,299,301,303,306],{"class":69,"line":298},5,[67,300,166],{"class":165},[67,302,169],{"class":81},[67,304,305],{"class":172},"filtered",[67,307,176],{"class":81},[14,309,310],{},"Output:",[58,312,314],{"className":60,"code":313,"language":62,"meta":63,"style":63},"[5, 12, 8, 20]\n[12, 20]\n",[37,315,316,337],{"__ignoreMap":63},[67,317,318,321,323,325,327,329,331,333,335],{"class":69,"line":70},[67,319,320],{"class":81},"[",[67,322,230],{"class":85},[67,324,89],{"class":81},[67,326,235],{"class":85},[67,328,89],{"class":81},[67,330,240],{"class":85},[67,332,89],{"class":81},[67,334,245],{"class":85},[67,336,115],{"class":81},[67,338,339,341,344,346,348],{"class":69,"line":118},[67,340,320],{"class":81},[67,342,343],{"class":85},"12",[67,345,89],{"class":81},[67,347,245],{"class":85},[67,349,115],{"class":81},[14,351,352,353,358],{},"If you need a refresher on lists first, see ",[354,355,357],"a",{"href":356},"\u002Flearn\u002Fpython-lists-explained-beginner-guide","Python lists explained for beginners",".",[53,360,362],{"id":361},"filter-a-list-with-a-list-comprehension","Filter a list with a list comprehension",[14,364,365],{},"A list comprehension is the most common Python way to filter a list.",[14,367,368],{},"The basic pattern is:",[58,370,372],{"className":60,"code":371,"language":62,"meta":63,"style":63},"[item for item in items if condition]\n",[37,373,374],{"__ignoreMap":63},[67,375,376,378,381,383,386,388,391,393,396],{"class":69,"line":70},[67,377,320],{"class":81},[67,379,380],{"class":73},"item ",[67,382,132],{"class":131},[67,384,385],{"class":73}," item ",[67,387,138],{"class":131},[67,389,390],{"class":73}," items ",[67,392,144],{"class":131},[67,394,395],{"class":73}," condition",[67,397,115],{"class":81},[14,399,400],{},"Here:",[21,402,403,409,415],{},[24,404,405,408],{},[37,406,407],{},"item"," is the current value",[24,410,411,414],{},[37,412,413],{},"items"," is the original list",[24,416,417,420],{},[37,418,419],{},"if condition"," decides whether the item is kept",[14,422,423],{},"Example: keep only even numbers.",[58,425,427],{"className":60,"code":426,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 4, 5, 6]\neven_numbers = [n for n in numbers if n % 2 == 0]\n\nprint(even_numbers)\n",[37,428,429,461,493,497],{"__ignoreMap":63},[67,430,431,433,435,437,439,441,443,445,447,449,451,453,455,457,459],{"class":69,"line":70},[67,432,74],{"class":73},[67,434,78],{"class":77},[67,436,82],{"class":81},[67,438,86],{"class":85},[67,440,89],{"class":81},[67,442,92],{"class":85},[67,444,89],{"class":81},[67,446,97],{"class":85},[67,448,89],{"class":81},[67,450,102],{"class":85},[67,452,89],{"class":81},[67,454,107],{"class":85},[67,456,89],{"class":81},[67,458,112],{"class":85},[67,460,115],{"class":81},[67,462,463,465,467,469,471,473,475,477,479,481,483,485,487,489,491],{"class":69,"line":118},[67,464,121],{"class":73},[67,466,78],{"class":77},[67,468,82],{"class":81},[67,470,128],{"class":73},[67,472,132],{"class":131},[67,474,135],{"class":73},[67,476,138],{"class":131},[67,478,141],{"class":73},[67,480,144],{"class":131},[67,482,135],{"class":73},[67,484,149],{"class":77},[67,486,92],{"class":85},[67,488,154],{"class":77},[67,490,157],{"class":85},[67,492,115],{"class":81},[67,494,495],{"class":69,"line":162},[67,496,284],{"emptyLinePlaceholder":283},[67,498,499,501,503,505],{"class":69,"line":179},[67,500,166],{"class":165},[67,502,169],{"class":81},[67,504,173],{"class":172},[67,506,176],{"class":81},[14,508,310],{},[58,510,512],{"className":60,"code":511,"language":62,"meta":63,"style":63},"[2, 4, 6]\n",[37,513,514],{"__ignoreMap":63},[67,515,516,518,521,523,525,527,529],{"class":69,"line":70},[67,517,320],{"class":81},[67,519,520],{"class":85},"2",[67,522,89],{"class":81},[67,524,102],{"class":85},[67,526,89],{"class":81},[67,528,112],{"class":85},[67,530,115],{"class":81},[532,533,535],"h3",{"id":534},"how-this-works","How this works",[14,537,538],{},"Python checks each number one by one:",[21,540,541,551,560],{},[24,542,543,546,547,550],{},[37,544,545],{},"1 % 2 == 0"," → ",[37,548,549],{},"False"," → leave it out",[24,552,553,546,556,559],{},[37,554,555],{},"2 % 2 == 0",[37,557,558],{},"True"," → keep it",[24,561,562,546,565,550],{},[37,563,564],{},"3 % 2 == 0",[37,566,549],{},[14,568,569,570,358],{},"If you want more practice with this syntax, see ",[354,571,573],{"href":572},"\u002Fhow-to\u002Fhow-to-use-list-comprehensions-in-python\u002F","how to use list comprehensions in Python",[53,575,577],{"id":576},"filter-strings-from-a-list","Filter strings from a list",[14,579,580],{},"You can also filter text values.",[532,582,584],{"id":583},"keep-names-longer-than-4-letters","Keep names longer than 4 letters",[58,586,588],{"className":60,"code":587,"language":62,"meta":63,"style":63},"names = [\"Sam\", \"Olivia\", \"Liam\", \"Emily\", \"Noah\"]\nlong_names = [name for name in names if len(name) > 4]\n\nprint(long_names)\n",[37,589,590,648,690,694],{"__ignoreMap":63},[67,591,592,595,597,599,603,607,609,611,614,617,619,621,623,626,628,630,632,635,637,639,641,644,646],{"class":69,"line":70},[67,593,594],{"class":73},"names ",[67,596,78],{"class":77},[67,598,82],{"class":81},[67,600,602],{"class":601},"sjJ54","\"",[67,604,606],{"class":605},"s_sjI","Sam",[67,608,602],{"class":601},[67,610,89],{"class":81},[67,612,613],{"class":601}," \"",[67,615,616],{"class":605},"Olivia",[67,618,602],{"class":601},[67,620,89],{"class":81},[67,622,613],{"class":601},[67,624,625],{"class":605},"Liam",[67,627,602],{"class":601},[67,629,89],{"class":81},[67,631,613],{"class":601},[67,633,634],{"class":605},"Emily",[67,636,602],{"class":601},[67,638,89],{"class":81},[67,640,613],{"class":601},[67,642,643],{"class":605},"Noah",[67,645,602],{"class":601},[67,647,115],{"class":81},[67,649,650,653,655,657,660,662,665,667,670,672,675,677,680,683,686,688],{"class":69,"line":118},[67,651,652],{"class":73},"long_names ",[67,654,78],{"class":77},[67,656,82],{"class":81},[67,658,659],{"class":73},"name ",[67,661,132],{"class":131},[67,663,664],{"class":73}," name ",[67,666,138],{"class":131},[67,668,669],{"class":73}," names ",[67,671,144],{"class":131},[67,673,674],{"class":165}," len",[67,676,169],{"class":81},[67,678,679],{"class":172},"name",[67,681,682],{"class":81},")",[67,684,685],{"class":77}," >",[67,687,102],{"class":85},[67,689,115],{"class":81},[67,691,692],{"class":69,"line":162},[67,693,284],{"emptyLinePlaceholder":283},[67,695,696,698,700,703],{"class":69,"line":179},[67,697,166],{"class":165},[67,699,169],{"class":81},[67,701,702],{"class":172},"long_names",[67,704,176],{"class":81},[14,706,310],{},[58,708,710],{"className":60,"code":709,"language":62,"meta":63,"style":63},"['Olivia', 'Emily']\n",[37,711,712],{"__ignoreMap":63},[67,713,714,716,719,721,723,725,728,730,732],{"class":69,"line":70},[67,715,320],{"class":81},[67,717,718],{"class":601},"'",[67,720,616],{"class":605},[67,722,718],{"class":601},[67,724,89],{"class":81},[67,726,727],{"class":601}," '",[67,729,634],{"class":605},[67,731,718],{"class":601},[67,733,115],{"class":81},[14,735,736,737,740],{},"The condition is ",[37,738,739],{},"len(name) > 4",", so only names with more than 4 letters are kept.",[532,742,744],{"id":743},"keep-words-starting-with-a-specific-letter","Keep words starting with a specific letter",[58,746,748],{"className":60,"code":747,"language":62,"meta":63,"style":63},"words = [\"apple\", \"banana\", \"avocado\", \"grape\"]\na_words = [word for word in words if word.startswith(\"a\")]\n\nprint(a_words)\n",[37,749,750,795,838,842],{"__ignoreMap":63},[67,751,752,755,757,759,761,764,766,768,770,773,775,777,779,782,784,786,788,791,793],{"class":69,"line":70},[67,753,754],{"class":73},"words ",[67,756,78],{"class":77},[67,758,82],{"class":81},[67,760,602],{"class":601},[67,762,763],{"class":605},"apple",[67,765,602],{"class":601},[67,767,89],{"class":81},[67,769,613],{"class":601},[67,771,772],{"class":605},"banana",[67,774,602],{"class":601},[67,776,89],{"class":81},[67,778,613],{"class":601},[67,780,781],{"class":605},"avocado",[67,783,602],{"class":601},[67,785,89],{"class":81},[67,787,613],{"class":601},[67,789,790],{"class":605},"grape",[67,792,602],{"class":601},[67,794,115],{"class":81},[67,796,797,800,802,804,807,809,812,814,817,819,822,824,827,829,831,833,835],{"class":69,"line":118},[67,798,799],{"class":73},"a_words ",[67,801,78],{"class":77},[67,803,82],{"class":81},[67,805,806],{"class":73},"word ",[67,808,132],{"class":131},[67,810,811],{"class":73}," word ",[67,813,138],{"class":131},[67,815,816],{"class":73}," words ",[67,818,144],{"class":131},[67,820,821],{"class":73}," word",[67,823,358],{"class":81},[67,825,826],{"class":172},"startswith",[67,828,169],{"class":81},[67,830,602],{"class":601},[67,832,354],{"class":605},[67,834,602],{"class":601},[67,836,837],{"class":81},")]\n",[67,839,840],{"class":69,"line":162},[67,841,284],{"emptyLinePlaceholder":283},[67,843,844,846,848,851],{"class":69,"line":179},[67,845,166],{"class":165},[67,847,169],{"class":81},[67,849,850],{"class":172},"a_words",[67,852,176],{"class":81},[14,854,310],{},[58,856,858],{"className":60,"code":857,"language":62,"meta":63,"style":63},"['apple', 'avocado']\n",[37,859,860],{"__ignoreMap":63},[67,861,862,864,866,868,870,872,874,876,878],{"class":69,"line":70},[67,863,320],{"class":81},[67,865,718],{"class":601},[67,867,763],{"class":605},[67,869,718],{"class":601},[67,871,89],{"class":81},[67,873,727],{"class":601},[67,875,781],{"class":605},[67,877,718],{"class":601},[67,879,115],{"class":81},[14,881,882,883,886],{},"Here, ",[37,884,885],{},"startswith(\"a\")"," checks each word one by one.",[53,888,890,891],{"id":889},"filter-a-list-with-filter","Filter a list with ",[37,892,50],{},[14,894,895,896,358],{},"Python also has a built-in function called ",[37,897,50],{},[14,899,900],{},"It needs:",[21,902,903,911],{},[24,904,905,906,908,909],{},"a function that returns ",[37,907,558],{}," or ",[37,910,549],{},[24,912,913],{},"a list or other iterable to check",[14,915,916],{},"Example:",[58,918,920],{"className":60,"code":919,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 4, 5, 6]\n\ndef is_even(n):\n    return n % 2 == 0\n\nresult = filter(is_even, numbers)\neven_numbers = list(result)\n\nprint(even_numbers)\n",[37,921,922,954,958,977,993,997,1020,1038,1043],{"__ignoreMap":63},[67,923,924,926,928,930,932,934,936,938,940,942,944,946,948,950,952],{"class":69,"line":70},[67,925,74],{"class":73},[67,927,78],{"class":77},[67,929,82],{"class":81},[67,931,86],{"class":85},[67,933,89],{"class":81},[67,935,92],{"class":85},[67,937,89],{"class":81},[67,939,97],{"class":85},[67,941,89],{"class":81},[67,943,102],{"class":85},[67,945,89],{"class":81},[67,947,107],{"class":85},[67,949,89],{"class":81},[67,951,112],{"class":85},[67,953,115],{"class":81},[67,955,956],{"class":69,"line":118},[67,957,284],{"emptyLinePlaceholder":283},[67,959,960,964,968,970,974],{"class":69,"line":162},[67,961,963],{"class":962},"sbsja","def",[67,965,967],{"class":966},"sGLFI"," is_even",[67,969,169],{"class":81},[67,971,973],{"class":972},"sFwrP","n",[67,975,976],{"class":81},"):\n",[67,978,979,982,984,986,988,990],{"class":69,"line":179},[67,980,981],{"class":131},"    return",[67,983,135],{"class":73},[67,985,149],{"class":77},[67,987,92],{"class":85},[67,989,154],{"class":77},[67,991,992],{"class":85}," 0\n",[67,994,995],{"class":69,"line":298},[67,996,284],{"emptyLinePlaceholder":283},[67,998,1000,1003,1005,1008,1010,1013,1015,1018],{"class":69,"line":999},6,[67,1001,1002],{"class":73},"result ",[67,1004,78],{"class":77},[67,1006,1007],{"class":165}," filter",[67,1009,169],{"class":81},[67,1011,1012],{"class":172},"is_even",[67,1014,89],{"class":81},[67,1016,1017],{"class":172}," numbers",[67,1019,176],{"class":81},[67,1021,1023,1025,1027,1031,1033,1036],{"class":69,"line":1022},7,[67,1024,121],{"class":73},[67,1026,78],{"class":77},[67,1028,1030],{"class":1029},"sZMiF"," list",[67,1032,169],{"class":81},[67,1034,1035],{"class":172},"result",[67,1037,176],{"class":81},[67,1039,1041],{"class":69,"line":1040},8,[67,1042,284],{"emptyLinePlaceholder":283},[67,1044,1046,1048,1050,1052],{"class":69,"line":1045},9,[67,1047,166],{"class":165},[67,1049,169],{"class":81},[67,1051,173],{"class":172},[67,1053,176],{"class":81},[14,1055,310],{},[58,1057,1058],{"className":60,"code":511,"language":62,"meta":63,"style":63},[37,1059,1060],{"__ignoreMap":63},[67,1061,1062,1064,1066,1068,1070,1072,1074],{"class":69,"line":70},[67,1063,320],{"class":81},[67,1065,520],{"class":85},[67,1067,89],{"class":81},[67,1069,102],{"class":85},[67,1071,89],{"class":81},[67,1073,112],{"class":85},[67,1075,115],{"class":81},[532,1077,1079,1080,1082],{"id":1078},"important-filter-does-not-return-a-list","Important: ",[37,1081,50],{}," does not return a list",[14,1084,1085,1087,1088,1091],{},[37,1086,50],{}," returns a ",[44,1089,1090],{},"filter object",", not a normal list.",[14,1093,1094,1095,1098],{},"That is why beginners usually wrap it with ",[37,1096,1097],{},"list()",":",[58,1100,1102],{"className":60,"code":1101,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 4]\nresult = filter(lambda n: n > 2, numbers)\n\nprint(result)\nprint(list(result))\n",[37,1103,1104,1128,1158,1162,1172],{"__ignoreMap":63},[67,1105,1106,1108,1110,1112,1114,1116,1118,1120,1122,1124,1126],{"class":69,"line":70},[67,1107,74],{"class":73},[67,1109,78],{"class":77},[67,1111,82],{"class":81},[67,1113,86],{"class":85},[67,1115,89],{"class":81},[67,1117,92],{"class":85},[67,1119,89],{"class":81},[67,1121,97],{"class":85},[67,1123,89],{"class":81},[67,1125,102],{"class":85},[67,1127,115],{"class":81},[67,1129,1130,1132,1134,1136,1138,1141,1144,1146,1148,1150,1152,1154,1156],{"class":69,"line":118},[67,1131,1002],{"class":73},[67,1133,78],{"class":77},[67,1135,1007],{"class":165},[67,1137,169],{"class":81},[67,1139,1140],{"class":962},"lambda",[67,1142,1143],{"class":972}," n",[67,1145,1098],{"class":81},[67,1147,135],{"class":172},[67,1149,273],{"class":77},[67,1151,92],{"class":85},[67,1153,89],{"class":81},[67,1155,1017],{"class":172},[67,1157,176],{"class":81},[67,1159,1160],{"class":69,"line":162},[67,1161,284],{"emptyLinePlaceholder":283},[67,1163,1164,1166,1168,1170],{"class":69,"line":179},[67,1165,166],{"class":165},[67,1167,169],{"class":81},[67,1169,1035],{"class":172},[67,1171,176],{"class":81},[67,1173,1174,1176,1178,1181,1183,1185],{"class":69,"line":298},[67,1175,166],{"class":165},[67,1177,169],{"class":81},[67,1179,1180],{"class":1029},"list",[67,1182,169],{"class":81},[67,1184,1035],{"class":172},[67,1186,1187],{"class":81},"))\n",[14,1189,1190],{},"Possible output:",[58,1192,1194],{"className":60,"code":1193,"language":62,"meta":63,"style":63},"\u003Cfilter object at 0x...>\n[3, 4]\n",[37,1195,1196,1221],{"__ignoreMap":63},[67,1197,1198,1201,1204,1207,1210,1214,1218],{"class":69,"line":70},[67,1199,1200],{"class":77},"\u003C",[67,1202,1203],{"class":165},"filter",[67,1205,1206],{"class":1029}," object",[67,1208,1209],{"class":73}," at ",[67,1211,1213],{"class":1212},"srjyR","0x",[67,1215,1217],{"class":1216},"s_hVV","...",[67,1219,1220],{"class":77},">\n",[67,1222,1223,1225,1228,1230,1232],{"class":69,"line":118},[67,1224,320],{"class":81},[67,1226,1227],{"class":85},"3",[67,1229,89],{"class":81},[67,1231,102],{"class":85},[67,1233,115],{"class":81},[14,1235,1236,1237,358],{},"For simple cases, list comprehensions are usually easier to read. If you want to learn more about this built-in function, see the ",[354,1238,1240,1241,1243],{"href":1239},"\u002Freference\u002Fpython-filter-function-explained","Python ",[37,1242,50],{}," function explained",[53,1245,1247],{"id":1246},"filter-out-empty-values","Filter out empty values",[14,1249,1250],{},"A very common task is removing empty strings.",[58,1252,1254],{"className":60,"code":1253,"language":62,"meta":63,"style":63},"items = [\"\", \"apple\", \"\", \"banana\", \"orange\", \"\"]\nfiltered = [item for item in items if item]\n\nprint(filtered)\n",[37,1255,1256,1304,1329,1333],{"__ignoreMap":63},[67,1257,1258,1261,1263,1265,1268,1270,1272,1274,1276,1278,1281,1283,1285,1287,1289,1291,1293,1296,1298,1300,1302],{"class":69,"line":70},[67,1259,1260],{"class":73},"items ",[67,1262,78],{"class":77},[67,1264,82],{"class":81},[67,1266,1267],{"class":601},"\"\"",[67,1269,89],{"class":81},[67,1271,613],{"class":601},[67,1273,763],{"class":605},[67,1275,602],{"class":601},[67,1277,89],{"class":81},[67,1279,1280],{"class":601}," \"\"",[67,1282,89],{"class":81},[67,1284,613],{"class":601},[67,1286,772],{"class":605},[67,1288,602],{"class":601},[67,1290,89],{"class":81},[67,1292,613],{"class":601},[67,1294,1295],{"class":605},"orange",[67,1297,602],{"class":601},[67,1299,89],{"class":81},[67,1301,1280],{"class":601},[67,1303,115],{"class":81},[67,1305,1306,1308,1310,1312,1314,1316,1318,1320,1322,1324,1327],{"class":69,"line":118},[67,1307,252],{"class":73},[67,1309,78],{"class":77},[67,1311,82],{"class":81},[67,1313,380],{"class":73},[67,1315,132],{"class":131},[67,1317,385],{"class":73},[67,1319,138],{"class":131},[67,1321,390],{"class":73},[67,1323,144],{"class":131},[67,1325,1326],{"class":73}," item",[67,1328,115],{"class":81},[67,1330,1331],{"class":69,"line":162},[67,1332,284],{"emptyLinePlaceholder":283},[67,1334,1335,1337,1339,1341],{"class":69,"line":179},[67,1336,166],{"class":165},[67,1338,169],{"class":81},[67,1340,305],{"class":172},[67,1342,176],{"class":81},[14,1344,310],{},[58,1346,1348],{"className":60,"code":1347,"language":62,"meta":63,"style":63},"['apple', 'banana', 'orange']\n",[37,1349,1350],{"__ignoreMap":63},[67,1351,1352,1354,1356,1358,1360,1362,1364,1366,1368,1370,1372,1374,1376],{"class":69,"line":70},[67,1353,320],{"class":81},[67,1355,718],{"class":601},[67,1357,763],{"class":605},[67,1359,718],{"class":601},[67,1361,89],{"class":81},[67,1363,727],{"class":601},[67,1365,772],{"class":605},[67,1367,718],{"class":601},[67,1369,89],{"class":81},[67,1371,727],{"class":601},[67,1373,1295],{"class":605},[67,1375,718],{"class":601},[67,1377,115],{"class":81},[532,1379,1381,1382,1385],{"id":1380},"why-if-item-works","Why ",[37,1383,1384],{},"if item"," works",[14,1387,1388],{},"In Python:",[21,1390,1391,1399],{},[24,1392,1393,1394,1396,1397],{},"an empty string ",[37,1395,1267],{}," is treated as ",[37,1398,549],{},[24,1400,1401,1402,1396,1405],{},"a non-empty string like ",[37,1403,1404],{},"\"apple\"",[37,1406,558],{},[14,1408,1409,1410,1412],{},"So ",[37,1411,1384],{}," keeps only the non-empty values.",[14,1414,1415,1416,1098],{},"You can do the same with ",[37,1417,50],{},[58,1419,1421],{"className":60,"code":1420,"language":62,"meta":63,"style":63},"items = [\"\", \"apple\", \"\", \"banana\"]\nfiltered = list(filter(None, items))\n\nprint(filtered)\n",[37,1422,1423,1455,1480,1484],{"__ignoreMap":63},[67,1424,1425,1427,1429,1431,1433,1435,1437,1439,1441,1443,1445,1447,1449,1451,1453],{"class":69,"line":70},[67,1426,1260],{"class":73},[67,1428,78],{"class":77},[67,1430,82],{"class":81},[67,1432,1267],{"class":601},[67,1434,89],{"class":81},[67,1436,613],{"class":601},[67,1438,763],{"class":605},[67,1440,602],{"class":601},[67,1442,89],{"class":81},[67,1444,1280],{"class":601},[67,1446,89],{"class":81},[67,1448,613],{"class":601},[67,1450,772],{"class":605},[67,1452,602],{"class":601},[67,1454,115],{"class":81},[67,1456,1457,1459,1461,1463,1465,1467,1469,1473,1475,1478],{"class":69,"line":118},[67,1458,252],{"class":73},[67,1460,78],{"class":77},[67,1462,1030],{"class":1029},[67,1464,169],{"class":81},[67,1466,1203],{"class":165},[67,1468,169],{"class":81},[67,1470,1472],{"class":1471},"s39Yj","None",[67,1474,89],{"class":81},[67,1476,1477],{"class":172}," items",[67,1479,1187],{"class":81},[67,1481,1482],{"class":69,"line":162},[67,1483,284],{"emptyLinePlaceholder":283},[67,1485,1486,1488,1490,1492],{"class":69,"line":179},[67,1487,166],{"class":165},[67,1489,169],{"class":81},[67,1491,305],{"class":172},[67,1493,176],{"class":81},[14,1495,310],{},[58,1497,1499],{"className":60,"code":1498,"language":62,"meta":63,"style":63},"['apple', 'banana']\n",[37,1500,1501],{"__ignoreMap":63},[67,1502,1503,1505,1507,1509,1511,1513,1515,1517,1519],{"class":69,"line":70},[67,1504,320],{"class":81},[67,1506,718],{"class":601},[67,1508,763],{"class":605},[67,1510,718],{"class":601},[67,1512,89],{"class":81},[67,1514,727],{"class":601},[67,1516,772],{"class":605},[67,1518,718],{"class":601},[67,1520,115],{"class":81},[14,1522,1523],{},"This is short and useful, but the list comprehension version is often easier for beginners to understand.",[53,1525,1527],{"id":1526},"filter-a-list-of-dictionaries","Filter a list of dictionaries",[14,1529,1530],{},"Filtering a list of dictionaries is also common.",[14,1532,1533],{},"Example: keep only people who are age 18 or older.",[58,1535,1537],{"className":60,"code":1536,"language":62,"meta":63,"style":63},"people = [\n    {\"name\": \"Anna\", \"age\": 17},\n    {\"name\": \"Ben\", \"age\": 21},\n    {\"name\": \"Cara\", \"age\": 18}\n]\n\nadults = [person for person in people if person[\"age\"] >= 18]\n\nprint(adults)\n",[37,1538,1539,1549,1586,1620,1655,1659,1663,1708,1712],{"__ignoreMap":63},[67,1540,1541,1544,1546],{"class":69,"line":70},[67,1542,1543],{"class":73},"people ",[67,1545,78],{"class":77},[67,1547,1548],{"class":81}," [\n",[67,1550,1551,1554,1556,1558,1560,1562,1564,1567,1569,1571,1573,1576,1578,1580,1583],{"class":69,"line":118},[67,1552,1553],{"class":81},"    {",[67,1555,602],{"class":601},[67,1557,679],{"class":605},[67,1559,602],{"class":601},[67,1561,1098],{"class":81},[67,1563,613],{"class":601},[67,1565,1566],{"class":605},"Anna",[67,1568,602],{"class":601},[67,1570,89],{"class":81},[67,1572,613],{"class":601},[67,1574,1575],{"class":605},"age",[67,1577,602],{"class":601},[67,1579,1098],{"class":81},[67,1581,1582],{"class":85}," 17",[67,1584,1585],{"class":81},"},\n",[67,1587,1588,1590,1592,1594,1596,1598,1600,1603,1605,1607,1609,1611,1613,1615,1618],{"class":69,"line":162},[67,1589,1553],{"class":81},[67,1591,602],{"class":601},[67,1593,679],{"class":605},[67,1595,602],{"class":601},[67,1597,1098],{"class":81},[67,1599,613],{"class":601},[67,1601,1602],{"class":605},"Ben",[67,1604,602],{"class":601},[67,1606,89],{"class":81},[67,1608,613],{"class":601},[67,1610,1575],{"class":605},[67,1612,602],{"class":601},[67,1614,1098],{"class":81},[67,1616,1617],{"class":85}," 21",[67,1619,1585],{"class":81},[67,1621,1622,1624,1626,1628,1630,1632,1634,1637,1639,1641,1643,1645,1647,1649,1652],{"class":69,"line":179},[67,1623,1553],{"class":81},[67,1625,602],{"class":601},[67,1627,679],{"class":605},[67,1629,602],{"class":601},[67,1631,1098],{"class":81},[67,1633,613],{"class":601},[67,1635,1636],{"class":605},"Cara",[67,1638,602],{"class":601},[67,1640,89],{"class":81},[67,1642,613],{"class":601},[67,1644,1575],{"class":605},[67,1646,602],{"class":601},[67,1648,1098],{"class":81},[67,1650,1651],{"class":85}," 18",[67,1653,1654],{"class":81},"}\n",[67,1656,1657],{"class":69,"line":298},[67,1658,115],{"class":81},[67,1660,1661],{"class":69,"line":999},[67,1662,284],{"emptyLinePlaceholder":283},[67,1664,1665,1668,1670,1672,1675,1677,1680,1682,1685,1687,1690,1692,1694,1696,1698,1701,1704,1706],{"class":69,"line":1022},[67,1666,1667],{"class":73},"adults ",[67,1669,78],{"class":77},[67,1671,82],{"class":81},[67,1673,1674],{"class":73},"person ",[67,1676,132],{"class":131},[67,1678,1679],{"class":73}," person ",[67,1681,138],{"class":131},[67,1683,1684],{"class":73}," people ",[67,1686,144],{"class":131},[67,1688,1689],{"class":73}," person",[67,1691,320],{"class":81},[67,1693,602],{"class":601},[67,1695,1575],{"class":605},[67,1697,602],{"class":601},[67,1699,1700],{"class":81},"]",[67,1702,1703],{"class":77}," >=",[67,1705,1651],{"class":85},[67,1707,115],{"class":81},[67,1709,1710],{"class":69,"line":1040},[67,1711,284],{"emptyLinePlaceholder":283},[67,1713,1714,1716,1718,1721],{"class":69,"line":1045},[67,1715,166],{"class":165},[67,1717,169],{"class":81},[67,1719,1720],{"class":172},"adults",[67,1722,176],{"class":81},[14,1724,310],{},[58,1726,1728],{"className":60,"code":1727,"language":62,"meta":63,"style":63},"[{'name': 'Ben', 'age': 21}, {'name': 'Cara', 'age': 18}]\n",[37,1729,1730],{"__ignoreMap":63},[67,1731,1732,1735,1737,1739,1741,1743,1745,1747,1749,1751,1753,1755,1757,1759,1761,1764,1767,1769,1771,1773,1775,1777,1779,1781,1783,1785,1787,1789,1791,1793],{"class":69,"line":70},[67,1733,1734],{"class":81},"[{",[67,1736,718],{"class":601},[67,1738,679],{"class":605},[67,1740,718],{"class":601},[67,1742,1098],{"class":81},[67,1744,727],{"class":601},[67,1746,1602],{"class":605},[67,1748,718],{"class":601},[67,1750,89],{"class":81},[67,1752,727],{"class":601},[67,1754,1575],{"class":605},[67,1756,718],{"class":601},[67,1758,1098],{"class":81},[67,1760,1617],{"class":85},[67,1762,1763],{"class":81},"},",[67,1765,1766],{"class":81}," {",[67,1768,718],{"class":601},[67,1770,679],{"class":605},[67,1772,718],{"class":601},[67,1774,1098],{"class":81},[67,1776,727],{"class":601},[67,1778,1636],{"class":605},[67,1780,718],{"class":601},[67,1782,89],{"class":81},[67,1784,727],{"class":601},[67,1786,1575],{"class":605},[67,1788,718],{"class":601},[67,1790,1098],{"class":81},[67,1792,1651],{"class":85},[67,1794,1795],{"class":81},"}]\n",[532,1797,1799],{"id":1798},"how-it-works","How it works",[14,1801,1802,1803,1806,1807,1809],{},"Inside the condition, ",[37,1804,1805],{},"person[\"age\"]"," gets the ",[37,1808,1575],{}," value from each dictionary.",[14,1811,1812,1813,1816],{},"If that value is ",[37,1814,1815],{},"18"," or more, the dictionary is kept.",[532,1818,1820],{"id":1819},"watch-out-for-missing-keys","Watch out for missing keys",[14,1822,1823,1824,1827],{},"This will fail if one dictionary does not have an ",[37,1825,1826],{},"\"age\""," key.",[58,1829,1831],{"className":60,"code":1830,"language":62,"meta":63,"style":63},"people = [\n    {\"name\": \"Anna\", \"age\": 17},\n    {\"name\": \"Ben\"},\n    {\"name\": \"Cara\", \"age\": 18}\n]\n\nadults = [person for person in people if person[\"age\"] >= 18]\n",[37,1832,1833,1841,1873,1893,1925,1929,1933],{"__ignoreMap":63},[67,1834,1835,1837,1839],{"class":69,"line":70},[67,1836,1543],{"class":73},[67,1838,78],{"class":77},[67,1840,1548],{"class":81},[67,1842,1843,1845,1847,1849,1851,1853,1855,1857,1859,1861,1863,1865,1867,1869,1871],{"class":69,"line":118},[67,1844,1553],{"class":81},[67,1846,602],{"class":601},[67,1848,679],{"class":605},[67,1850,602],{"class":601},[67,1852,1098],{"class":81},[67,1854,613],{"class":601},[67,1856,1566],{"class":605},[67,1858,602],{"class":601},[67,1860,89],{"class":81},[67,1862,613],{"class":601},[67,1864,1575],{"class":605},[67,1866,602],{"class":601},[67,1868,1098],{"class":81},[67,1870,1582],{"class":85},[67,1872,1585],{"class":81},[67,1874,1875,1877,1879,1881,1883,1885,1887,1889,1891],{"class":69,"line":162},[67,1876,1553],{"class":81},[67,1878,602],{"class":601},[67,1880,679],{"class":605},[67,1882,602],{"class":601},[67,1884,1098],{"class":81},[67,1886,613],{"class":601},[67,1888,1602],{"class":605},[67,1890,602],{"class":601},[67,1892,1585],{"class":81},[67,1894,1895,1897,1899,1901,1903,1905,1907,1909,1911,1913,1915,1917,1919,1921,1923],{"class":69,"line":179},[67,1896,1553],{"class":81},[67,1898,602],{"class":601},[67,1900,679],{"class":605},[67,1902,602],{"class":601},[67,1904,1098],{"class":81},[67,1906,613],{"class":601},[67,1908,1636],{"class":605},[67,1910,602],{"class":601},[67,1912,89],{"class":81},[67,1914,613],{"class":601},[67,1916,1575],{"class":605},[67,1918,602],{"class":601},[67,1920,1098],{"class":81},[67,1922,1651],{"class":85},[67,1924,1654],{"class":81},[67,1926,1927],{"class":69,"line":298},[67,1928,115],{"class":81},[67,1930,1931],{"class":69,"line":999},[67,1932,284],{"emptyLinePlaceholder":283},[67,1934,1935,1937,1939,1941,1943,1945,1947,1949,1951,1953,1955,1957,1959,1961,1963,1965,1967,1969],{"class":69,"line":1022},[67,1936,1667],{"class":73},[67,1938,78],{"class":77},[67,1940,82],{"class":81},[67,1942,1674],{"class":73},[67,1944,132],{"class":131},[67,1946,1679],{"class":73},[67,1948,138],{"class":131},[67,1950,1684],{"class":73},[67,1952,144],{"class":131},[67,1954,1689],{"class":73},[67,1956,320],{"class":81},[67,1958,602],{"class":601},[67,1960,1575],{"class":605},[67,1962,602],{"class":601},[67,1964,1700],{"class":81},[67,1966,1703],{"class":77},[67,1968,1651],{"class":85},[67,1970,115],{"class":81},[14,1972,1973,1974,358],{},"This raises a ",[37,1975,1976],{},"KeyError",[14,1978,1979,1980,1098],{},"A safer version uses ",[37,1981,1982],{},".get()",[58,1984,1986],{"className":60,"code":1985,"language":62,"meta":63,"style":63},"people = [\n    {\"name\": \"Anna\", \"age\": 17},\n    {\"name\": \"Ben\"},\n    {\"name\": \"Cara\", \"age\": 18}\n]\n\nadults = [person for person in people if person.get(\"age\", 0) >= 18]\n\nprint(adults)\n",[37,1987,1988,1996,2028,2048,2080,2084,2088,2135,2139],{"__ignoreMap":63},[67,1989,1990,1992,1994],{"class":69,"line":70},[67,1991,1543],{"class":73},[67,1993,78],{"class":77},[67,1995,1548],{"class":81},[67,1997,1998,2000,2002,2004,2006,2008,2010,2012,2014,2016,2018,2020,2022,2024,2026],{"class":69,"line":118},[67,1999,1553],{"class":81},[67,2001,602],{"class":601},[67,2003,679],{"class":605},[67,2005,602],{"class":601},[67,2007,1098],{"class":81},[67,2009,613],{"class":601},[67,2011,1566],{"class":605},[67,2013,602],{"class":601},[67,2015,89],{"class":81},[67,2017,613],{"class":601},[67,2019,1575],{"class":605},[67,2021,602],{"class":601},[67,2023,1098],{"class":81},[67,2025,1582],{"class":85},[67,2027,1585],{"class":81},[67,2029,2030,2032,2034,2036,2038,2040,2042,2044,2046],{"class":69,"line":162},[67,2031,1553],{"class":81},[67,2033,602],{"class":601},[67,2035,679],{"class":605},[67,2037,602],{"class":601},[67,2039,1098],{"class":81},[67,2041,613],{"class":601},[67,2043,1602],{"class":605},[67,2045,602],{"class":601},[67,2047,1585],{"class":81},[67,2049,2050,2052,2054,2056,2058,2060,2062,2064,2066,2068,2070,2072,2074,2076,2078],{"class":69,"line":179},[67,2051,1553],{"class":81},[67,2053,602],{"class":601},[67,2055,679],{"class":605},[67,2057,602],{"class":601},[67,2059,1098],{"class":81},[67,2061,613],{"class":601},[67,2063,1636],{"class":605},[67,2065,602],{"class":601},[67,2067,89],{"class":81},[67,2069,613],{"class":601},[67,2071,1575],{"class":605},[67,2073,602],{"class":601},[67,2075,1098],{"class":81},[67,2077,1651],{"class":85},[67,2079,1654],{"class":81},[67,2081,2082],{"class":69,"line":298},[67,2083,115],{"class":81},[67,2085,2086],{"class":69,"line":999},[67,2087,284],{"emptyLinePlaceholder":283},[67,2089,2090,2092,2094,2096,2098,2100,2102,2104,2106,2108,2110,2112,2115,2117,2119,2121,2123,2125,2127,2129,2131,2133],{"class":69,"line":1022},[67,2091,1667],{"class":73},[67,2093,78],{"class":77},[67,2095,82],{"class":81},[67,2097,1674],{"class":73},[67,2099,132],{"class":131},[67,2101,1679],{"class":73},[67,2103,138],{"class":131},[67,2105,1684],{"class":73},[67,2107,144],{"class":131},[67,2109,1689],{"class":73},[67,2111,358],{"class":81},[67,2113,2114],{"class":172},"get",[67,2116,169],{"class":81},[67,2118,602],{"class":601},[67,2120,1575],{"class":605},[67,2122,602],{"class":601},[67,2124,89],{"class":81},[67,2126,157],{"class":85},[67,2128,682],{"class":81},[67,2130,1703],{"class":77},[67,2132,1651],{"class":85},[67,2134,115],{"class":81},[67,2136,2137],{"class":69,"line":1040},[67,2138,284],{"emptyLinePlaceholder":283},[67,2140,2141,2143,2145,2147],{"class":69,"line":1045},[67,2142,166],{"class":165},[67,2144,169],{"class":81},[67,2146,1720],{"class":172},[67,2148,176],{"class":81},[14,2150,310],{},[58,2152,2154],{"className":60,"code":2153,"language":62,"meta":63,"style":63},"[{'name': 'Cara', 'age': 18}]\n",[37,2155,2156],{"__ignoreMap":63},[67,2157,2158,2160,2162,2164,2166,2168,2170,2172,2174,2176,2178,2180,2182,2184,2186],{"class":69,"line":70},[67,2159,1734],{"class":81},[67,2161,718],{"class":601},[67,2163,679],{"class":605},[67,2165,718],{"class":601},[67,2167,1098],{"class":81},[67,2169,727],{"class":601},[67,2171,1636],{"class":605},[67,2173,718],{"class":601},[67,2175,89],{"class":81},[67,2177,727],{"class":601},[67,2179,1575],{"class":605},[67,2181,718],{"class":601},[67,2183,1098],{"class":81},[67,2185,1651],{"class":85},[67,2187,1795],{"class":81},[14,2189,2190,2191,358],{},"If you run into this problem, see ",[354,2192,2194],{"href":2193},"\u002Ferrors\u002Fkeyerror-in-python-causes-and-fixes","KeyError in Python: causes and fixes",[53,2196,2198],{"id":2197},"common-beginner-mistakes-when-filtering","Common beginner mistakes when filtering",[14,2200,2201],{},"Here are some common problems beginners run into.",[532,2203,2205],{"id":2204},"expecting-the-original-list-to-change","Expecting the original list to change",[14,2207,2208],{},"Filtering usually creates a new list.",[58,2210,2212],{"className":60,"code":2211,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 4]\nfiltered = [n for n in numbers if n > 2]\n\nprint(numbers)   # original list\nprint(filtered)  # new filtered list\n",[37,2213,2214,2238,2266,2270,2283],{"__ignoreMap":63},[67,2215,2216,2218,2220,2222,2224,2226,2228,2230,2232,2234,2236],{"class":69,"line":70},[67,2217,74],{"class":73},[67,2219,78],{"class":77},[67,2221,82],{"class":81},[67,2223,86],{"class":85},[67,2225,89],{"class":81},[67,2227,92],{"class":85},[67,2229,89],{"class":81},[67,2231,97],{"class":85},[67,2233,89],{"class":81},[67,2235,102],{"class":85},[67,2237,115],{"class":81},[67,2239,2240,2242,2244,2246,2248,2250,2252,2254,2256,2258,2260,2262,2264],{"class":69,"line":118},[67,2241,252],{"class":73},[67,2243,78],{"class":77},[67,2245,82],{"class":81},[67,2247,128],{"class":73},[67,2249,132],{"class":131},[67,2251,135],{"class":73},[67,2253,138],{"class":131},[67,2255,141],{"class":73},[67,2257,144],{"class":131},[67,2259,135],{"class":73},[67,2261,273],{"class":77},[67,2263,92],{"class":85},[67,2265,115],{"class":81},[67,2267,2268],{"class":69,"line":162},[67,2269,284],{"emptyLinePlaceholder":283},[67,2271,2272,2274,2276,2278,2280],{"class":69,"line":179},[67,2273,166],{"class":165},[67,2275,169],{"class":81},[67,2277,293],{"class":172},[67,2279,682],{"class":81},[67,2281,2282],{"class":182},"   # original list\n",[67,2284,2285,2287,2289,2291,2293],{"class":69,"line":298},[67,2286,166],{"class":165},[67,2288,169],{"class":81},[67,2290,305],{"class":172},[67,2292,682],{"class":81},[67,2294,2295],{"class":182},"  # new filtered list\n",[532,2297,2299,2300,2302,2303],{"id":2298},"using-instead-of","Using ",[37,2301,78],{}," instead of ",[37,2304,2305],{},"==",[14,2307,2308,2309,2311],{},"Use ",[37,2310,2305],{}," when comparing values.",[14,2313,2314],{},"Wrong:",[58,2316,2318],{"className":60,"code":2317,"language":62,"meta":63,"style":63},"# This is invalid Python\n# [n for n in numbers if n = 2]\n",[37,2319,2320,2325],{"__ignoreMap":63},[67,2321,2322],{"class":69,"line":70},[67,2323,2324],{"class":182},"# This is invalid Python\n",[67,2326,2327],{"class":69,"line":118},[67,2328,2329],{"class":182},"# [n for n in numbers if n = 2]\n",[14,2331,2332],{},"Correct:",[58,2334,2336],{"className":60,"code":2335,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 2]\ntwos = [n for n in numbers if n == 2]\n\nprint(twos)\n",[37,2337,2338,2362,2391,2395],{"__ignoreMap":63},[67,2339,2340,2342,2344,2346,2348,2350,2352,2354,2356,2358,2360],{"class":69,"line":70},[67,2341,74],{"class":73},[67,2343,78],{"class":77},[67,2345,82],{"class":81},[67,2347,86],{"class":85},[67,2349,89],{"class":81},[67,2351,92],{"class":85},[67,2353,89],{"class":81},[67,2355,97],{"class":85},[67,2357,89],{"class":81},[67,2359,92],{"class":85},[67,2361,115],{"class":81},[67,2363,2364,2367,2369,2371,2373,2375,2377,2379,2381,2383,2385,2387,2389],{"class":69,"line":118},[67,2365,2366],{"class":73},"twos ",[67,2368,78],{"class":77},[67,2370,82],{"class":81},[67,2372,128],{"class":73},[67,2374,132],{"class":131},[67,2376,135],{"class":73},[67,2378,138],{"class":131},[67,2380,141],{"class":73},[67,2382,144],{"class":131},[67,2384,135],{"class":73},[67,2386,2305],{"class":77},[67,2388,92],{"class":85},[67,2390,115],{"class":81},[67,2392,2393],{"class":69,"line":162},[67,2394,284],{"emptyLinePlaceholder":283},[67,2396,2397,2399,2401,2404],{"class":69,"line":179},[67,2398,166],{"class":165},[67,2400,169],{"class":81},[67,2402,2403],{"class":172},"twos",[67,2405,176],{"class":81},[14,2407,310],{},[58,2409,2411],{"className":60,"code":2410,"language":62,"meta":63,"style":63},"[2, 2]\n",[37,2412,2413],{"__ignoreMap":63},[67,2414,2415,2417,2419,2421,2423],{"class":69,"line":70},[67,2416,320],{"class":81},[67,2418,520],{"class":85},[67,2420,89],{"class":81},[67,2422,92],{"class":85},[67,2424,115],{"class":81},[532,2426,2428,2429,2431],{"id":2427},"forgetting-that-filter-returns-an-iterable","Forgetting that ",[37,2430,50],{}," returns an iterable",[14,2433,2434],{},"This can be confusing:",[58,2436,2438],{"className":60,"code":2437,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 4]\nresult = filter(lambda n: n > 2, numbers)\n\nprint(type(result))\n",[37,2439,2440,2464,2492,2496],{"__ignoreMap":63},[67,2441,2442,2444,2446,2448,2450,2452,2454,2456,2458,2460,2462],{"class":69,"line":70},[67,2443,74],{"class":73},[67,2445,78],{"class":77},[67,2447,82],{"class":81},[67,2449,86],{"class":85},[67,2451,89],{"class":81},[67,2453,92],{"class":85},[67,2455,89],{"class":81},[67,2457,97],{"class":85},[67,2459,89],{"class":81},[67,2461,102],{"class":85},[67,2463,115],{"class":81},[67,2465,2466,2468,2470,2472,2474,2476,2478,2480,2482,2484,2486,2488,2490],{"class":69,"line":118},[67,2467,1002],{"class":73},[67,2469,78],{"class":77},[67,2471,1007],{"class":165},[67,2473,169],{"class":81},[67,2475,1140],{"class":962},[67,2477,1143],{"class":972},[67,2479,1098],{"class":81},[67,2481,135],{"class":172},[67,2483,273],{"class":77},[67,2485,92],{"class":85},[67,2487,89],{"class":81},[67,2489,1017],{"class":172},[67,2491,176],{"class":81},[67,2493,2494],{"class":69,"line":162},[67,2495,284],{"emptyLinePlaceholder":283},[67,2497,2498,2500,2502,2505,2507,2509],{"class":69,"line":179},[67,2499,166],{"class":165},[67,2501,169],{"class":81},[67,2503,2504],{"class":1029},"type",[67,2506,169],{"class":81},[67,2508,1035],{"class":172},[67,2510,1187],{"class":81},[14,2512,310],{},[58,2514,2516],{"className":60,"code":2515,"language":62,"meta":63,"style":63},"\u003Cclass 'filter'>\n",[37,2517,2518],{"__ignoreMap":63},[67,2519,2520,2522,2525,2527,2529,2531],{"class":69,"line":70},[67,2521,1200],{"class":77},[67,2523,2524],{"class":962},"class",[67,2526,727],{"class":601},[67,2528,1203],{"class":605},[67,2530,718],{"class":601},[67,2532,1220],{"class":77},[14,2534,2535],{},"If you want a list, convert it:",[58,2537,2539],{"className":60,"code":2538,"language":62,"meta":63,"style":63},"filtered = list(result)\nprint(filtered)\n",[37,2540,2541,2555],{"__ignoreMap":63},[67,2542,2543,2545,2547,2549,2551,2553],{"class":69,"line":70},[67,2544,252],{"class":73},[67,2546,78],{"class":77},[67,2548,1030],{"class":1029},[67,2550,169],{"class":81},[67,2552,1035],{"class":172},[67,2554,176],{"class":81},[67,2556,2557,2559,2561,2563],{"class":69,"line":118},[67,2558,166],{"class":165},[67,2560,169],{"class":81},[67,2562,305],{"class":172},[67,2564,176],{"class":81},[532,2566,2568],{"id":2567},"writing-a-condition-that-does-not-behave-as-expected","Writing a condition that does not behave as expected",[14,2570,2571],{},"Sometimes the condition is not checking what you think it is.",[14,2573,2574],{},"For example:",[58,2576,2578],{"className":60,"code":2577,"language":62,"meta":63,"style":63},"numbers = [0, 1, 2, 3]\nfiltered = [n for n in numbers if n]\n\nprint(filtered)\n",[37,2579,2580,2606,2630,2634],{"__ignoreMap":63},[67,2581,2582,2584,2586,2588,2591,2593,2596,2598,2600,2602,2604],{"class":69,"line":70},[67,2583,74],{"class":73},[67,2585,78],{"class":77},[67,2587,82],{"class":81},[67,2589,2590],{"class":85},"0",[67,2592,89],{"class":81},[67,2594,2595],{"class":85}," 1",[67,2597,89],{"class":81},[67,2599,92],{"class":85},[67,2601,89],{"class":81},[67,2603,97],{"class":85},[67,2605,115],{"class":81},[67,2607,2608,2610,2612,2614,2616,2618,2620,2622,2624,2626,2628],{"class":69,"line":118},[67,2609,252],{"class":73},[67,2611,78],{"class":77},[67,2613,82],{"class":81},[67,2615,128],{"class":73},[67,2617,132],{"class":131},[67,2619,135],{"class":73},[67,2621,138],{"class":131},[67,2623,141],{"class":73},[67,2625,144],{"class":131},[67,2627,1143],{"class":73},[67,2629,115],{"class":81},[67,2631,2632],{"class":69,"line":162},[67,2633,284],{"emptyLinePlaceholder":283},[67,2635,2636,2638,2640,2642],{"class":69,"line":179},[67,2637,166],{"class":165},[67,2639,169],{"class":81},[67,2641,305],{"class":172},[67,2643,176],{"class":81},[14,2645,310],{},[58,2647,2649],{"className":60,"code":2648,"language":62,"meta":63,"style":63},"[1, 2, 3]\n",[37,2650,2651],{"__ignoreMap":63},[67,2652,2653,2655,2657,2659,2661,2663,2665],{"class":69,"line":70},[67,2654,320],{"class":81},[67,2656,86],{"class":85},[67,2658,89],{"class":81},[67,2660,92],{"class":85},[67,2662,89],{"class":81},[67,2664,97],{"class":85},[67,2666,115],{"class":81},[14,2668,2669,2670,2672,2673,1396,2675,2677],{},"This removes ",[37,2671,2590],{}," because ",[37,2674,2590],{},[37,2676,549],{}," in Python.",[532,2679,2681],{"id":2680},"removing-items-from-a-list-while-looping-over-it","Removing items from a list while looping over it",[14,2683,2684],{},"This often causes skipped values or unexpected results.",[14,2686,2687],{},"Avoid this:",[58,2689,2691],{"className":60,"code":2690,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 4, 5]\n\nfor n in numbers:\n    if n % 2 == 0:\n        numbers.remove(n)\n\nprint(numbers)\n",[37,2692,2693,2721,2725,2738,2755,2771,2775],{"__ignoreMap":63},[67,2694,2695,2697,2699,2701,2703,2705,2707,2709,2711,2713,2715,2717,2719],{"class":69,"line":70},[67,2696,74],{"class":73},[67,2698,78],{"class":77},[67,2700,82],{"class":81},[67,2702,86],{"class":85},[67,2704,89],{"class":81},[67,2706,92],{"class":85},[67,2708,89],{"class":81},[67,2710,97],{"class":85},[67,2712,89],{"class":81},[67,2714,102],{"class":85},[67,2716,89],{"class":81},[67,2718,107],{"class":85},[67,2720,115],{"class":81},[67,2722,2723],{"class":69,"line":118},[67,2724,284],{"emptyLinePlaceholder":283},[67,2726,2727,2729,2731,2733,2735],{"class":69,"line":162},[67,2728,132],{"class":131},[67,2730,135],{"class":73},[67,2732,138],{"class":131},[67,2734,1017],{"class":73},[67,2736,2737],{"class":81},":\n",[67,2739,2740,2743,2745,2747,2749,2751,2753],{"class":69,"line":179},[67,2741,2742],{"class":131},"    if",[67,2744,135],{"class":73},[67,2746,149],{"class":77},[67,2748,92],{"class":85},[67,2750,154],{"class":77},[67,2752,157],{"class":85},[67,2754,2737],{"class":81},[67,2756,2757,2760,2762,2765,2767,2769],{"class":69,"line":298},[67,2758,2759],{"class":73},"        numbers",[67,2761,358],{"class":81},[67,2763,2764],{"class":172},"remove",[67,2766,169],{"class":81},[67,2768,973],{"class":172},[67,2770,176],{"class":81},[67,2772,2773],{"class":69,"line":999},[67,2774,284],{"emptyLinePlaceholder":283},[67,2776,2777,2779,2781,2783],{"class":69,"line":1022},[67,2778,166],{"class":165},[67,2780,169],{"class":81},[67,2782,293],{"class":172},[67,2784,176],{"class":81},[14,2786,2787],{},"Instead, create a new filtered list:",[58,2789,2791],{"className":60,"code":2790,"language":62,"meta":63,"style":63},"numbers = [1, 2, 3, 4, 5]\nodd_numbers = [n for n in numbers if n % 2 != 0]\n\nprint(odd_numbers)\n",[37,2792,2793,2821,2855,2859],{"__ignoreMap":63},[67,2794,2795,2797,2799,2801,2803,2805,2807,2809,2811,2813,2815,2817,2819],{"class":69,"line":70},[67,2796,74],{"class":73},[67,2798,78],{"class":77},[67,2800,82],{"class":81},[67,2802,86],{"class":85},[67,2804,89],{"class":81},[67,2806,92],{"class":85},[67,2808,89],{"class":81},[67,2810,97],{"class":85},[67,2812,89],{"class":81},[67,2814,102],{"class":85},[67,2816,89],{"class":81},[67,2818,107],{"class":85},[67,2820,115],{"class":81},[67,2822,2823,2826,2828,2830,2832,2834,2836,2838,2840,2842,2844,2846,2848,2851,2853],{"class":69,"line":118},[67,2824,2825],{"class":73},"odd_numbers ",[67,2827,78],{"class":77},[67,2829,82],{"class":81},[67,2831,128],{"class":73},[67,2833,132],{"class":131},[67,2835,135],{"class":73},[67,2837,138],{"class":131},[67,2839,141],{"class":73},[67,2841,144],{"class":131},[67,2843,135],{"class":73},[67,2845,149],{"class":77},[67,2847,92],{"class":85},[67,2849,2850],{"class":77}," !=",[67,2852,157],{"class":85},[67,2854,115],{"class":81},[67,2856,2857],{"class":69,"line":162},[67,2858,284],{"emptyLinePlaceholder":283},[67,2860,2861,2863,2865,2868],{"class":69,"line":179},[67,2862,166],{"class":165},[67,2864,169],{"class":81},[67,2866,2867],{"class":172},"odd_numbers",[67,2869,176],{"class":81},[14,2871,2872,2873,358],{},"If you are practicing list loops, see ",[354,2874,2876],{"href":2875},"\u002Fhow-to\u002Fhow-to-loop-through-a-list-in-python\u002F","how to loop through a list in Python",[53,2878,2880],{"id":2879},"when-to-use-each-approach","When to use each approach",[14,2882,2883,2884,2886],{},"Use a ",[44,2885,46],{}," when:",[21,2888,2889,2892,2895],{},[24,2890,2891],{},"the condition is simple",[24,2893,2894],{},"you want the result as a list",[24,2896,2897],{},"you want code that is easy to read",[14,2899,2308,2900,2886],{},[44,2901,2902],{},[37,2903,50],{},[21,2905,2906,2909,2912],{},[24,2907,2908],{},"you already have a function that checks each item",[24,2910,2911],{},"you want to reuse that function",[24,2913,2914],{},"the code reads clearly with that function",[14,2916,2917],{},"In general:",[21,2919,2920,2923,2926],{},[24,2921,2922],{},"choose the version that is easiest to understand",[24,2924,2925],{},"avoid very complex one-line conditions",[24,2927,2928],{},"prefer readability over clever code",[53,2930,2932],{"id":2931},"faq","FAQ",[532,2934,2936],{"id":2935},"does-filtering-change-the-original-list","Does filtering change the original list?",[14,2938,2939],{},"Usually no. Most filtering examples create a new list and leave the original list unchanged.",[532,2941,2943,2944,2946],{"id":2942},"should-i-use-list-comprehension-or-filter","Should I use list comprehension or ",[37,2945,50],{},"?",[14,2948,2949],{},"For beginners, list comprehensions are usually easier to read and more common in everyday Python code.",[532,2951,2953],{"id":2952},"can-i-filter-numbers-strings-and-dictionaries","Can I filter numbers, strings, and dictionaries?",[14,2955,2956],{},"Yes. You can filter any list as long as you can write a condition that checks each item.",[532,2958,2960,2961,2963],{"id":2959},"why-does-filter-not-print-a-normal-list","Why does ",[37,2962,50],{}," not print a normal list?",[14,2965,2966,2967,2969,2970,2972],{},"Because ",[37,2968,50],{}," returns a filter object. Wrap it in ",[37,2971,1097],{}," if you want a list.",[53,2974,2976],{"id":2975},"see-also","See also",[21,2978,2979,2983,2989,2994,2999,3005],{},[24,2980,2981],{},[354,2982,357],{"href":356},[24,2984,2985],{},[354,2986,2988],{"href":2987},"\u002Fhow-to\u002Fhow-to-check-if-a-value-exists-in-a-list-in-python\u002F","How to check if a value exists in a list in Python",[24,2990,2991],{},[354,2992,2993],{"href":2875},"How to loop through a list in Python",[24,2995,2996],{},[354,2997,2998],{"href":572},"How to use list comprehensions in Python",[24,3000,3001],{},[354,3002,1240,3003,1243],{"href":1239},[37,3004,50],{},[24,3006,3007],{},[354,3008,2194],{"href":2193},[3010,3011,3012],"style",{},"html pre.shiki code .su5hD, html code.shiki .su5hD{--shiki-light:#90A4AE;--shiki-default:#24292E;--shiki-dark:#E1E4E8}html pre.shiki code .smGrS, html code.shiki .smGrS{--shiki-light:#39ADB5;--shiki-default:#D73A49;--shiki-dark:#F97583}html pre.shiki code .sP7_E, html code.shiki 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.sZMiF{--shiki-light:#E2931D;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .srjyR, html code.shiki .srjyR{--shiki-light:#90A4AE;--shiki-light-font-style:inherit;--shiki-default:#B31D28;--shiki-default-font-style:italic;--shiki-dark:#FDAEB7;--shiki-dark-font-style:italic}html pre.shiki code .s_hVV, html code.shiki .s_hVV{--shiki-light:#90A4AE;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .s39Yj, html code.shiki .s39Yj{--shiki-light:#39ADB5;--shiki-default:#005CC5;--shiki-dark:#79B8FF}",{"title":63,"searchDepth":118,"depth":118,"links":3014},[3015,3016,3017,3020,3024,3029,3033,3037,3046,3047,3055],{"id":55,"depth":118,"text":56},{"id":189,"depth":118,"text":190},{"id":361,"depth":118,"text":362,"children":3018},[3019],{"id":534,"depth":162,"text":535},{"id":576,"depth":118,"text":577,"children":3021},[3022,3023],{"id":583,"depth":162,"text":584},{"id":743,"depth":162,"text":744},{"id":889,"depth":118,"text":3025,"children":3026},"Filter a list with filter()",[3027],{"id":1078,"depth":162,"text":3028},"Important: filter() does not return a list",{"id":1246,"depth":118,"text":1247,"children":3030},[3031],{"id":1380,"depth":162,"text":3032},"Why if item works",{"id":1526,"depth":118,"text":1527,"children":3034},[3035,3036],{"id":1798,"depth":162,"text":1799},{"id":1819,"depth":162,"text":1820},{"id":2197,"depth":118,"text":2198,"children":3038},[3039,3040,3042,3044,3045],{"id":2204,"depth":162,"text":2205},{"id":2298,"depth":162,"text":3041},"Using = instead of ==",{"id":2427,"depth":162,"text":3043},"Forgetting that filter() returns an iterable",{"id":2567,"depth":162,"text":2568},{"id":2680,"depth":162,"text":2681},{"id":2879,"depth":118,"text":2880},{"id":2931,"depth":118,"text":2932,"children":3048},[3049,3050,3052,3053],{"id":2935,"depth":162,"text":2936},{"id":2942,"depth":162,"text":3051},"Should I use list comprehension or filter()?",{"id":2952,"depth":162,"text":2953},{"id":2959,"depth":162,"text":3054},"Why does filter() not print a normal list?",{"id":2975,"depth":118,"text":2976},"Master how to filter a list in python in our comprehensive Python beginner guide.","md",{},"\u002Fhow-to\u002Fhow-to-filter-a-list-in-python",{"title":5,"description":3056},"how-to\u002Fhow-to-filter-a-list-in-python","ScGnvSYGdpO8QKtk-N2_AHmcaZCq_gcapSH35z7RGi4",1777585503723]