[{"data":1,"prerenderedAt":1752},["ShallowReactive",2],{"doc-\u002Freference\u002Fpython-list-length-len":3},{"id":4,"title":5,"body":6,"description":1745,"extension":1746,"meta":1747,"navigation":360,"path":1748,"seo":1749,"stem":1750,"__hash__":1751},"content\u002Freference\u002Fpython-list-length-len.md","Python List Length (len)",{"type":7,"value":8,"toc":1718},"minimark",[9,19,30,109,112,121,128,133,155,162,168,171,174,193,196,257,259,267,278,290,294,300,373,375,383,386,407,410,461,465,470,500,502,511,514,595,597,617,625,629,638,641,706,708,716,719,722,771,773,781,787,791,802,805,808,848,851,890,895,899,901,936,939,941,979,983,989,991,1046,1048,1056,1064,1067,1091,1094,1150,1163,1166,1229,1231,1240,1247,1253,1256,1259,1318,1321,1335,1342,1349,1355,1358,1372,1375,1474,1476,1496,1499,1590,1592,1618,1625,1633,1637,1641,1647,1655,1661,1665,1668,1675,1684,1688,1714],[10,11,13,14,18],"h1",{"id":12},"python-list-length-len","Python List Length (",[15,16,17],"code",{},"len",")",[20,21,22,23,26,27,29],"p",{},"Learn how to get the number of items in a Python list using ",[15,24,25],{},"len()",". This page focuses on the basic use of ",[15,28,25],{}," with lists, common beginner mistakes, and simple examples.",[31,32,37],"pre",{"className":33,"code":34,"language":35,"meta":36,"style":36},"language-python shiki shiki-themes material-theme-lighter github-light github-dark","numbers = [10, 20, 30]\ncount = len(numbers)\nprint(count)\n","python","",[15,38,39,74,96],{"__ignoreMap":36},[40,41,44,48,52,56,60,63,66,68,71],"span",{"class":42,"line":43},"line",1,[40,45,47],{"class":46},"su5hD","numbers ",[40,49,51],{"class":50},"smGrS","=",[40,53,55],{"class":54},"sP7_E"," [",[40,57,59],{"class":58},"srdBf","10",[40,61,62],{"class":54},",",[40,64,65],{"class":58}," 20",[40,67,62],{"class":54},[40,69,70],{"class":58}," 30",[40,72,73],{"class":54},"]\n",[40,75,77,80,82,86,89,93],{"class":42,"line":76},2,[40,78,79],{"class":46},"count ",[40,81,51],{"class":50},[40,83,85],{"class":84},"sptTA"," len",[40,87,88],{"class":54},"(",[40,90,92],{"class":91},"slqww","numbers",[40,94,95],{"class":54},")\n",[40,97,99,102,104,107],{"class":42,"line":98},3,[40,100,101],{"class":84},"print",[40,103,88],{"class":54},[40,105,106],{"class":91},"count",[40,108,95],{"class":54},[20,110,111],{},"Output:",[31,113,115],{"className":33,"code":114,"language":35,"meta":36,"style":36},"3\n",[15,116,117],{"__ignoreMap":36},[40,118,119],{"class":42,"line":43},[40,120,114],{"class":58},[20,122,123,124,127],{},"Use ",[15,125,126],{},"len(list_name)"," to get how many items are in a list.",[129,130,132],"h2",{"id":131},"what-this-page-covers","What this page covers",[134,135,136,143,149,152],"ul",{},[137,138,139,140,142],"li",{},"How ",[15,141,25],{}," works with Python lists",[137,144,145,146,148],{},"What value ",[15,147,25],{}," returns",[137,150,151],{},"Simple examples with empty and non-empty lists",[137,153,154],{},"Common mistakes beginners make",[129,156,158,159,161],{"id":157},"what-len-returns-for-a-list","What ",[15,160,25],{}," returns for a list",[20,163,164,167],{},[15,165,166],{},"len(my_list)"," returns an integer.",[20,169,170],{},"That integer is the number of items in the list.",[20,172,173],{},"A few important points:",[134,175,176,179,187],{},[137,177,178],{},"It counts list items",[137,180,181,182,186],{},"It does ",[183,184,185],"strong",{},"not"," count characters inside a string item",[137,188,189,190],{},"An empty list returns ",[15,191,192],{},"0",[20,194,195],{},"Example:",[31,197,199],{"className":33,"code":198,"language":35,"meta":36,"style":36},"words = [\"cat\", \"elephant\", \"dog\"]\nprint(len(words))\n",[15,200,201,241],{"__ignoreMap":36},[40,202,203,206,208,210,214,218,220,222,225,228,230,232,234,237,239],{"class":42,"line":43},[40,204,205],{"class":46},"words ",[40,207,51],{"class":50},[40,209,55],{"class":54},[40,211,213],{"class":212},"sjJ54","\"",[40,215,217],{"class":216},"s_sjI","cat",[40,219,213],{"class":212},[40,221,62],{"class":54},[40,223,224],{"class":212}," \"",[40,226,227],{"class":216},"elephant",[40,229,213],{"class":212},[40,231,62],{"class":54},[40,233,224],{"class":212},[40,235,236],{"class":216},"dog",[40,238,213],{"class":212},[40,240,73],{"class":54},[40,242,243,245,247,249,251,254],{"class":42,"line":76},[40,244,101],{"class":84},[40,246,88],{"class":54},[40,248,17],{"class":84},[40,250,88],{"class":54},[40,252,253],{"class":91},"words",[40,255,256],{"class":54},"))\n",[20,258,111],{},[31,260,261],{"className":33,"code":114,"language":35,"meta":36,"style":36},[15,262,263],{"__ignoreMap":36},[40,264,265],{"class":42,"line":43},[40,266,114],{"class":58},[20,268,269,270,273,274,277],{},"Even though ",[15,271,272],{},"\"elephant\""," has many characters, it still counts as just ",[183,275,276],{},"one item"," in the list.",[20,279,280,281,289],{},"If you want a broader explanation of the function itself, see ",[282,283,285,286,288],"a",{"href":284},"\u002Freference\u002Fpython-len-function-explained\u002F","Python ",[15,287,25],{}," function explained",".",[129,291,293],{"id":292},"basic-example","Basic example",[20,295,296,297,299],{},"Create a list, pass it to ",[15,298,25],{},", and print the result.",[31,301,303],{"className":33,"code":302,"language":35,"meta":36,"style":36},"colors = [\"red\", \"green\", \"blue\"]\ncount = len(colors)\n\nprint(count)\n",[15,304,305,341,356,362],{"__ignoreMap":36},[40,306,307,310,312,314,316,319,321,323,325,328,330,332,334,337,339],{"class":42,"line":43},[40,308,309],{"class":46},"colors ",[40,311,51],{"class":50},[40,313,55],{"class":54},[40,315,213],{"class":212},[40,317,318],{"class":216},"red",[40,320,213],{"class":212},[40,322,62],{"class":54},[40,324,224],{"class":212},[40,326,327],{"class":216},"green",[40,329,213],{"class":212},[40,331,62],{"class":54},[40,333,224],{"class":212},[40,335,336],{"class":216},"blue",[40,338,213],{"class":212},[40,340,73],{"class":54},[40,342,343,345,347,349,351,354],{"class":42,"line":76},[40,344,79],{"class":46},[40,346,51],{"class":50},[40,348,85],{"class":84},[40,350,88],{"class":54},[40,352,353],{"class":91},"colors",[40,355,95],{"class":54},[40,357,358],{"class":42,"line":98},[40,359,361],{"emptyLinePlaceholder":360},true,"\n",[40,363,365,367,369,371],{"class":42,"line":364},4,[40,366,101],{"class":84},[40,368,88],{"class":54},[40,370,106],{"class":91},[40,372,95],{"class":54},[20,374,111],{},[31,376,377],{"className":33,"code":114,"language":35,"meta":36,"style":36},[15,378,379],{"__ignoreMap":36},[40,380,381],{"class":42,"line":43},[40,382,114],{"class":58},[20,384,385],{},"What happens here:",[134,387,388,393,402],{},[137,389,390,392],{},[15,391,353],{}," is a list with 3 items",[137,394,395,398,399],{},[15,396,397],{},"len(colors)"," returns ",[15,400,401],{},"3",[137,403,404,405],{},"That value is stored in ",[15,406,106],{},[20,408,409],{},"You can also print the result directly:",[31,411,413],{"className":33,"code":412,"language":35,"meta":36,"style":36},"colors = [\"red\", \"green\", \"blue\"]\nprint(len(colors))\n",[15,414,415,447],{"__ignoreMap":36},[40,416,417,419,421,423,425,427,429,431,433,435,437,439,441,443,445],{"class":42,"line":43},[40,418,309],{"class":46},[40,420,51],{"class":50},[40,422,55],{"class":54},[40,424,213],{"class":212},[40,426,318],{"class":216},[40,428,213],{"class":212},[40,430,62],{"class":54},[40,432,224],{"class":212},[40,434,327],{"class":216},[40,436,213],{"class":212},[40,438,62],{"class":54},[40,440,224],{"class":212},[40,442,336],{"class":216},[40,444,213],{"class":212},[40,446,73],{"class":54},[40,448,449,451,453,455,457,459],{"class":42,"line":76},[40,450,101],{"class":84},[40,452,88],{"class":54},[40,454,17],{"class":84},[40,456,88],{"class":54},[40,458,353],{"class":91},[40,460,256],{"class":54},[129,462,464],{"id":463},"empty-list-example","Empty list example",[20,466,467,468,289],{},"An empty list has no items, so its length is ",[15,469,192],{},[31,471,473],{"className":33,"code":472,"language":35,"meta":36,"style":36},"items = []\nprint(len(items))\n",[15,474,475,485],{"__ignoreMap":36},[40,476,477,480,482],{"class":42,"line":43},[40,478,479],{"class":46},"items ",[40,481,51],{"class":50},[40,483,484],{"class":54}," []\n",[40,486,487,489,491,493,495,498],{"class":42,"line":76},[40,488,101],{"class":84},[40,490,88],{"class":54},[40,492,17],{"class":84},[40,494,88],{"class":54},[40,496,497],{"class":91},"items",[40,499,256],{"class":54},[20,501,111],{},[31,503,505],{"className":33,"code":504,"language":35,"meta":36,"style":36},"0\n",[15,506,507],{"__ignoreMap":36},[40,508,509],{"class":42,"line":43},[40,510,504],{"class":58},[20,512,513],{},"This is useful when you want to check whether a list has anything in it before using an index.",[31,515,517],{"className":33,"code":516,"language":35,"meta":36,"style":36},"items = []\n\nif len(items) > 0:\n    print(items[0])\nelse:\n    print(\"The list is empty\")\n",[15,518,519,527,531,554,571,579],{"__ignoreMap":36},[40,520,521,523,525],{"class":42,"line":43},[40,522,479],{"class":46},[40,524,51],{"class":50},[40,526,484],{"class":54},[40,528,529],{"class":42,"line":76},[40,530,361],{"emptyLinePlaceholder":360},[40,532,533,537,539,541,543,545,548,551],{"class":42,"line":98},[40,534,536],{"class":535},"sVHd0","if",[40,538,85],{"class":84},[40,540,88],{"class":54},[40,542,497],{"class":91},[40,544,18],{"class":54},[40,546,547],{"class":50}," >",[40,549,550],{"class":58}," 0",[40,552,553],{"class":54},":\n",[40,555,556,559,561,563,566,568],{"class":42,"line":364},[40,557,558],{"class":84},"    print",[40,560,88],{"class":54},[40,562,497],{"class":91},[40,564,565],{"class":54},"[",[40,567,192],{"class":58},[40,569,570],{"class":54},"])\n",[40,572,574,577],{"class":42,"line":573},5,[40,575,576],{"class":535},"else",[40,578,553],{"class":54},[40,580,582,584,586,588,591,593],{"class":42,"line":581},6,[40,583,558],{"class":84},[40,585,88],{"class":54},[40,587,213],{"class":212},[40,589,590],{"class":216},"The list is empty",[40,592,213],{"class":212},[40,594,95],{"class":54},[20,596,111],{},[31,598,600],{"className":33,"code":599,"language":35,"meta":36,"style":36},"The list is empty\n",[15,601,602],{"__ignoreMap":36},[40,603,604,607,611,614],{"class":42,"line":43},[40,605,606],{"class":46},"The ",[40,608,610],{"class":609},"sZMiF","list",[40,612,613],{"class":50}," is",[40,615,616],{"class":46}," empty\n",[20,618,619,620,624],{},"If you are still learning how lists work, ",[282,621,623],{"href":622},"\u002Flearn\u002Fpython-lists-explained-beginner-guide\u002F","Python lists explained for beginners"," is a good next step.",[129,626,628],{"id":627},"nested-lists","Nested lists",[20,630,631,633,634,637],{},[15,632,25],{}," counts only the ",[183,635,636],{},"top-level items"," in a list.",[20,639,640],{},"A nested list counts as one item.",[31,642,644],{"className":33,"code":643,"language":35,"meta":36,"style":36},"data = [[1, 2], [3, 4], [5, 6]]\nprint(len(data))\n",[15,645,646,691],{"__ignoreMap":36},[40,647,648,651,653,656,659,661,664,667,669,671,673,676,678,680,683,685,688],{"class":42,"line":43},[40,649,650],{"class":46},"data ",[40,652,51],{"class":50},[40,654,655],{"class":54}," [[",[40,657,658],{"class":58},"1",[40,660,62],{"class":54},[40,662,663],{"class":58}," 2",[40,665,666],{"class":54},"],",[40,668,55],{"class":54},[40,670,401],{"class":58},[40,672,62],{"class":54},[40,674,675],{"class":58}," 4",[40,677,666],{"class":54},[40,679,55],{"class":54},[40,681,682],{"class":58},"5",[40,684,62],{"class":54},[40,686,687],{"class":58}," 6",[40,689,690],{"class":54},"]]\n",[40,692,693,695,697,699,701,704],{"class":42,"line":76},[40,694,101],{"class":84},[40,696,88],{"class":54},[40,698,17],{"class":84},[40,700,88],{"class":54},[40,702,703],{"class":91},"data",[40,705,256],{"class":54},[20,707,111],{},[31,709,710],{"className":33,"code":114,"language":35,"meta":36,"style":36},[15,711,712],{"__ignoreMap":36},[40,713,714],{"class":42,"line":43},[40,715,114],{"class":58},[20,717,718],{},"Here, the list contains 3 items, and each item is itself a list.",[20,720,721],{},"Another example:",[31,723,725],{"className":33,"code":724,"language":35,"meta":36,"style":36},"mixed = [1, [2, 3], 4]\nprint(len(mixed))\n",[15,726,727,756],{"__ignoreMap":36},[40,728,729,732,734,736,738,740,742,745,747,750,752,754],{"class":42,"line":43},[40,730,731],{"class":46},"mixed ",[40,733,51],{"class":50},[40,735,55],{"class":54},[40,737,658],{"class":58},[40,739,62],{"class":54},[40,741,55],{"class":54},[40,743,744],{"class":58},"2",[40,746,62],{"class":54},[40,748,749],{"class":58}," 3",[40,751,666],{"class":54},[40,753,675],{"class":58},[40,755,73],{"class":54},[40,757,758,760,762,764,766,769],{"class":42,"line":76},[40,759,101],{"class":84},[40,761,88],{"class":54},[40,763,17],{"class":84},[40,765,88],{"class":54},[40,767,768],{"class":91},"mixed",[40,770,256],{"class":54},[20,772,111],{},[31,774,775],{"className":33,"code":114,"language":35,"meta":36,"style":36},[15,776,777],{"__ignoreMap":36},[40,778,779],{"class":42,"line":43},[40,780,114],{"class":58},[20,782,269,783,786],{},[15,784,785],{},"[2, 3]"," contains 2 values, it is still only one item in the outer list.",[129,788,790],{"id":789},"common-beginner-mistakes","Common beginner mistakes",[792,793,795,796,799,800],"h3",{"id":794},"using-my_listlen-instead-of-lenmy_list","Using ",[15,797,798],{},"my_list.len()"," instead of ",[15,801,166],{},[20,803,804],{},"This is a very common mistake.",[20,806,807],{},"Wrong:",[31,809,811],{"className":33,"code":810,"language":35,"meta":36,"style":36},"numbers = [10, 20, 30]\nprint(numbers.len())\n",[15,812,813,833],{"__ignoreMap":36},[40,814,815,817,819,821,823,825,827,829,831],{"class":42,"line":43},[40,816,47],{"class":46},[40,818,51],{"class":50},[40,820,55],{"class":54},[40,822,59],{"class":58},[40,824,62],{"class":54},[40,826,65],{"class":58},[40,828,62],{"class":54},[40,830,70],{"class":58},[40,832,73],{"class":54},[40,834,835,837,839,841,843,845],{"class":42,"line":76},[40,836,101],{"class":84},[40,838,88],{"class":54},[40,840,92],{"class":91},[40,842,289],{"class":54},[40,844,17],{"class":91},[40,846,847],{"class":54},"())\n",[20,849,850],{},"Correct:",[31,852,854],{"className":33,"code":853,"language":35,"meta":36,"style":36},"numbers = [10, 20, 30]\nprint(len(numbers))\n",[15,855,856,876],{"__ignoreMap":36},[40,857,858,860,862,864,866,868,870,872,874],{"class":42,"line":43},[40,859,47],{"class":46},[40,861,51],{"class":50},[40,863,55],{"class":54},[40,865,59],{"class":58},[40,867,62],{"class":54},[40,869,65],{"class":58},[40,871,62],{"class":54},[40,873,70],{"class":58},[40,875,73],{"class":54},[40,877,878,880,882,884,886,888],{"class":42,"line":76},[40,879,101],{"class":84},[40,881,88],{"class":54},[40,883,17],{"class":84},[40,885,88],{"class":54},[40,887,92],{"class":91},[40,889,256],{"class":54},[20,891,892,894],{},[15,893,25],{}," is a built-in function. It is not a list method.",[792,896,898],{"id":897},"forgetting-parentheses","Forgetting parentheses",[20,900,807],{},[31,902,904],{"className":33,"code":903,"language":35,"meta":36,"style":36},"numbers = [10, 20, 30]\nprint(len)\n",[15,905,906,926],{"__ignoreMap":36},[40,907,908,910,912,914,916,918,920,922,924],{"class":42,"line":43},[40,909,47],{"class":46},[40,911,51],{"class":50},[40,913,55],{"class":54},[40,915,59],{"class":58},[40,917,62],{"class":54},[40,919,65],{"class":58},[40,921,62],{"class":54},[40,923,70],{"class":58},[40,925,73],{"class":54},[40,927,928,930,932,934],{"class":42,"line":76},[40,929,101],{"class":84},[40,931,88],{"class":54},[40,933,17],{"class":84},[40,935,95],{"class":54},[20,937,938],{},"This prints the function itself, not the list length.",[20,940,850],{},[31,942,943],{"className":33,"code":853,"language":35,"meta":36,"style":36},[15,944,945,965],{"__ignoreMap":36},[40,946,947,949,951,953,955,957,959,961,963],{"class":42,"line":43},[40,948,47],{"class":46},[40,950,51],{"class":50},[40,952,55],{"class":54},[40,954,59],{"class":58},[40,956,62],{"class":54},[40,958,65],{"class":58},[40,960,62],{"class":54},[40,962,70],{"class":58},[40,964,73],{"class":54},[40,966,967,969,971,973,975,977],{"class":42,"line":76},[40,968,101],{"class":84},[40,970,88],{"class":54},[40,972,17],{"class":84},[40,974,88],{"class":54},[40,976,92],{"class":91},[40,978,256],{"class":54},[792,980,982],{"id":981},"confusing-length-with-the-last-index","Confusing length with the last index",[20,984,985,986,988],{},"The length of a list is ",[183,987,185],{}," the same as the last index.",[20,990,195],{},[31,992,994],{"className":33,"code":993,"language":35,"meta":36,"style":36},"letters = [\"a\", \"b\", \"c\"]\nprint(len(letters))\n",[15,995,996,1031],{"__ignoreMap":36},[40,997,998,1001,1003,1005,1007,1009,1011,1013,1015,1018,1020,1022,1024,1027,1029],{"class":42,"line":43},[40,999,1000],{"class":46},"letters ",[40,1002,51],{"class":50},[40,1004,55],{"class":54},[40,1006,213],{"class":212},[40,1008,282],{"class":216},[40,1010,213],{"class":212},[40,1012,62],{"class":54},[40,1014,224],{"class":212},[40,1016,1017],{"class":216},"b",[40,1019,213],{"class":212},[40,1021,62],{"class":54},[40,1023,224],{"class":212},[40,1025,1026],{"class":216},"c",[40,1028,213],{"class":212},[40,1030,73],{"class":54},[40,1032,1033,1035,1037,1039,1041,1044],{"class":42,"line":76},[40,1034,101],{"class":84},[40,1036,88],{"class":54},[40,1038,17],{"class":84},[40,1040,88],{"class":54},[40,1042,1043],{"class":91},"letters",[40,1045,256],{"class":54},[20,1047,111],{},[31,1049,1050],{"className":33,"code":114,"language":35,"meta":36,"style":36},[15,1051,1052],{"__ignoreMap":36},[40,1053,1054],{"class":42,"line":43},[40,1055,114],{"class":58},[20,1057,1058,1059,1061,1062,289],{},"But the last index is ",[15,1060,744],{},", not ",[15,1063,401],{},[20,1065,1066],{},"Indexes are:",[134,1068,1069,1077,1084],{},[137,1070,1071,1073,1074],{},[15,1072,192],{}," for ",[15,1075,1076],{},"\"a\"",[137,1078,1079,1073,1081],{},[15,1080,658],{},[15,1082,1083],{},"\"b\"",[137,1085,1086,1073,1088],{},[15,1087,744],{},[15,1089,1090],{},"\"c\"",[20,1092,1093],{},"So this causes an error:",[31,1095,1097],{"className":33,"code":1096,"language":35,"meta":36,"style":36},"letters = [\"a\", \"b\", \"c\"]\nprint(letters[len(letters)])\n",[15,1098,1099,1131],{"__ignoreMap":36},[40,1100,1101,1103,1105,1107,1109,1111,1113,1115,1117,1119,1121,1123,1125,1127,1129],{"class":42,"line":43},[40,1102,1000],{"class":46},[40,1104,51],{"class":50},[40,1106,55],{"class":54},[40,1108,213],{"class":212},[40,1110,282],{"class":216},[40,1112,213],{"class":212},[40,1114,62],{"class":54},[40,1116,224],{"class":212},[40,1118,1017],{"class":216},[40,1120,213],{"class":212},[40,1122,62],{"class":54},[40,1124,224],{"class":212},[40,1126,1026],{"class":216},[40,1128,213],{"class":212},[40,1130,73],{"class":54},[40,1132,1133,1135,1137,1139,1141,1143,1145,1147],{"class":42,"line":76},[40,1134,101],{"class":84},[40,1136,88],{"class":54},[40,1138,1043],{"class":91},[40,1140,565],{"class":54},[40,1142,17],{"class":84},[40,1144,88],{"class":54},[40,1146,1043],{"class":91},[40,1148,1149],{"class":54},")])\n",[20,1151,1152,1153,1156,1157,1159,1160,1162],{},"Why? Because ",[15,1154,1155],{},"len(letters)"," is ",[15,1158,401],{},", and index ",[15,1161,401],{}," does not exist.",[20,1164,1165],{},"Use this instead:",[31,1167,1169],{"className":33,"code":1168,"language":35,"meta":36,"style":36},"letters = [\"a\", \"b\", \"c\"]\nprint(letters[len(letters) - 1])\n",[15,1170,1171,1203],{"__ignoreMap":36},[40,1172,1173,1175,1177,1179,1181,1183,1185,1187,1189,1191,1193,1195,1197,1199,1201],{"class":42,"line":43},[40,1174,1000],{"class":46},[40,1176,51],{"class":50},[40,1178,55],{"class":54},[40,1180,213],{"class":212},[40,1182,282],{"class":216},[40,1184,213],{"class":212},[40,1186,62],{"class":54},[40,1188,224],{"class":212},[40,1190,1017],{"class":216},[40,1192,213],{"class":212},[40,1194,62],{"class":54},[40,1196,224],{"class":212},[40,1198,1026],{"class":216},[40,1200,213],{"class":212},[40,1202,73],{"class":54},[40,1204,1205,1207,1209,1211,1213,1215,1217,1219,1221,1224,1227],{"class":42,"line":76},[40,1206,101],{"class":84},[40,1208,88],{"class":54},[40,1210,1043],{"class":91},[40,1212,565],{"class":54},[40,1214,17],{"class":84},[40,1216,88],{"class":54},[40,1218,1043],{"class":91},[40,1220,18],{"class":54},[40,1222,1223],{"class":50}," -",[40,1225,1226],{"class":58}," 1",[40,1228,570],{"class":54},[20,1230,111],{},[31,1232,1234],{"className":33,"code":1233,"language":35,"meta":36,"style":36},"c\n",[15,1235,1236],{"__ignoreMap":36},[40,1237,1238],{"class":42,"line":43},[40,1239,1233],{"class":46},[20,1241,1242,1243,289],{},"If you see an index problem here, read ",[282,1244,1246],{"href":1245},"\u002Ferrors\u002Findexerror-list-index-out-of-range-fix-explained\u002F","IndexError: list index out of range",[792,1248,795,1250,1252],{"id":1249},"using-len-on-the-wrong-variable",[15,1251,25],{}," on the wrong variable",[20,1254,1255],{},"Sometimes the code is correct, but the variable is not what you expect.",[20,1257,1258],{},"Use these debugging checks:",[31,1260,1262],{"className":33,"code":1261,"language":35,"meta":36,"style":36},"print(my_list)\nprint(len(my_list))\nprint(type(my_list))\nprint(my_list[0])\n",[15,1263,1264,1275,1289,1304],{"__ignoreMap":36},[40,1265,1266,1268,1270,1273],{"class":42,"line":43},[40,1267,101],{"class":84},[40,1269,88],{"class":54},[40,1271,1272],{"class":91},"my_list",[40,1274,95],{"class":54},[40,1276,1277,1279,1281,1283,1285,1287],{"class":42,"line":76},[40,1278,101],{"class":84},[40,1280,88],{"class":54},[40,1282,17],{"class":84},[40,1284,88],{"class":54},[40,1286,1272],{"class":91},[40,1288,256],{"class":54},[40,1290,1291,1293,1295,1298,1300,1302],{"class":42,"line":98},[40,1292,101],{"class":84},[40,1294,88],{"class":54},[40,1296,1297],{"class":609},"type",[40,1299,88],{"class":54},[40,1301,1272],{"class":91},[40,1303,256],{"class":54},[40,1305,1306,1308,1310,1312,1314,1316],{"class":42,"line":364},[40,1307,101],{"class":84},[40,1309,88],{"class":54},[40,1311,1272],{"class":91},[40,1313,565],{"class":54},[40,1315,192],{"class":58},[40,1317,570],{"class":54},[20,1319,1320],{},"These help you verify:",[134,1322,1323,1326,1329,1332],{},[137,1324,1325],{},"what the variable contains",[137,1327,1328],{},"how many items it has",[137,1330,1331],{},"whether it is really a list",[137,1333,1334],{},"what the first item is",[20,1336,1337,1338,1341],{},"Be careful with ",[15,1339,1340],{},"print(my_list[0])"," if the list might be empty.",[129,1343,1345,1346,1348],{"id":1344},"when-to-use-len-with-lists","When to use ",[15,1347,25],{}," with lists",[20,1350,1351,1352,1354],{},"You will often use ",[15,1353,25],{}," in real programs.",[20,1356,1357],{},"Common uses include:",[134,1359,1360,1363,1366,1369],{},[137,1361,1362],{},"Check if a list is empty",[137,1364,1365],{},"Control loops",[137,1367,1368],{},"Validate input or results",[137,1370,1371],{},"Compare the sizes of two lists",[20,1373,1374],{},"Example: comparing two lists",[31,1376,1378],{"className":33,"code":1377,"language":35,"meta":36,"style":36},"a = [1, 2, 3]\nb = [10, 20]\n\nprint(len(a))\nprint(len(b))\nprint(len(a) > len(b))\n",[15,1379,1380,1401,1418,1422,1436,1450],{"__ignoreMap":36},[40,1381,1382,1385,1387,1389,1391,1393,1395,1397,1399],{"class":42,"line":43},[40,1383,1384],{"class":46},"a ",[40,1386,51],{"class":50},[40,1388,55],{"class":54},[40,1390,658],{"class":58},[40,1392,62],{"class":54},[40,1394,663],{"class":58},[40,1396,62],{"class":54},[40,1398,749],{"class":58},[40,1400,73],{"class":54},[40,1402,1403,1406,1408,1410,1412,1414,1416],{"class":42,"line":76},[40,1404,1405],{"class":46},"b ",[40,1407,51],{"class":50},[40,1409,55],{"class":54},[40,1411,59],{"class":58},[40,1413,62],{"class":54},[40,1415,65],{"class":58},[40,1417,73],{"class":54},[40,1419,1420],{"class":42,"line":98},[40,1421,361],{"emptyLinePlaceholder":360},[40,1423,1424,1426,1428,1430,1432,1434],{"class":42,"line":364},[40,1425,101],{"class":84},[40,1427,88],{"class":54},[40,1429,17],{"class":84},[40,1431,88],{"class":54},[40,1433,282],{"class":91},[40,1435,256],{"class":54},[40,1437,1438,1440,1442,1444,1446,1448],{"class":42,"line":573},[40,1439,101],{"class":84},[40,1441,88],{"class":54},[40,1443,17],{"class":84},[40,1445,88],{"class":54},[40,1447,1017],{"class":91},[40,1449,256],{"class":54},[40,1451,1452,1454,1456,1458,1460,1462,1464,1466,1468,1470,1472],{"class":42,"line":581},[40,1453,101],{"class":84},[40,1455,88],{"class":54},[40,1457,17],{"class":84},[40,1459,88],{"class":54},[40,1461,282],{"class":91},[40,1463,18],{"class":54},[40,1465,547],{"class":50},[40,1467,85],{"class":84},[40,1469,88],{"class":54},[40,1471,1017],{"class":91},[40,1473,256],{"class":54},[20,1475,111],{},[31,1477,1479],{"className":33,"code":1478,"language":35,"meta":36,"style":36},"3\n2\nTrue\n",[15,1480,1481,1485,1490],{"__ignoreMap":36},[40,1482,1483],{"class":42,"line":43},[40,1484,114],{"class":58},[40,1486,1487],{"class":42,"line":76},[40,1488,1489],{"class":58},"2\n",[40,1491,1492],{"class":42,"line":98},[40,1493,1495],{"class":1494},"s39Yj","True\n",[20,1497,1498],{},"Example: using length in a loop",[31,1500,1502],{"className":33,"code":1501,"language":35,"meta":36,"style":36},"names = [\"Ana\", \"Ben\", \"Cara\"]\n\nfor i in range(len(names)):\n    print(i, names[i])\n",[15,1503,1504,1540,1544,1570],{"__ignoreMap":36},[40,1505,1506,1509,1511,1513,1515,1518,1520,1522,1524,1527,1529,1531,1533,1536,1538],{"class":42,"line":43},[40,1507,1508],{"class":46},"names ",[40,1510,51],{"class":50},[40,1512,55],{"class":54},[40,1514,213],{"class":212},[40,1516,1517],{"class":216},"Ana",[40,1519,213],{"class":212},[40,1521,62],{"class":54},[40,1523,224],{"class":212},[40,1525,1526],{"class":216},"Ben",[40,1528,213],{"class":212},[40,1530,62],{"class":54},[40,1532,224],{"class":212},[40,1534,1535],{"class":216},"Cara",[40,1537,213],{"class":212},[40,1539,73],{"class":54},[40,1541,1542],{"class":42,"line":76},[40,1543,361],{"emptyLinePlaceholder":360},[40,1545,1546,1549,1552,1555,1558,1560,1562,1564,1567],{"class":42,"line":98},[40,1547,1548],{"class":535},"for",[40,1550,1551],{"class":46}," i ",[40,1553,1554],{"class":535},"in",[40,1556,1557],{"class":84}," range",[40,1559,88],{"class":54},[40,1561,17],{"class":84},[40,1563,88],{"class":54},[40,1565,1566],{"class":91},"names",[40,1568,1569],{"class":54},")):\n",[40,1571,1572,1574,1576,1579,1581,1584,1586,1588],{"class":42,"line":364},[40,1573,558],{"class":84},[40,1575,88],{"class":54},[40,1577,1578],{"class":91},"i",[40,1580,62],{"class":54},[40,1582,1583],{"class":91}," names",[40,1585,565],{"class":54},[40,1587,1578],{"class":91},[40,1589,570],{"class":54},[20,1591,111],{},[31,1593,1595],{"className":33,"code":1594,"language":35,"meta":36,"style":36},"0 Ana\n1 Ben\n2 Cara\n",[15,1596,1597,1604,1611],{"__ignoreMap":36},[40,1598,1599,1601],{"class":42,"line":43},[40,1600,192],{"class":58},[40,1602,1603],{"class":46}," Ana\n",[40,1605,1606,1608],{"class":42,"line":76},[40,1607,658],{"class":58},[40,1609,1610],{"class":46}," Ben\n",[40,1612,1613,1615],{"class":42,"line":98},[40,1614,744],{"class":58},[40,1616,1617],{"class":46}," Cara\n",[20,1619,1620,1621,289],{},"This works, but if you want to practice looping through lists more safely and clearly, see ",[282,1622,1624],{"href":1623},"\u002Fhow-to\u002Fhow-to-loop-through-a-list-in-python\u002F","how to loop through a list in Python",[20,1626,1627,1628,1632],{},"You can also read ",[282,1629,1631],{"href":1630},"\u002Fhow-to\u002Fhow-to-get-the-length-of-a-list-in-python\u002F","how to get the length of a list in Python"," for a task-focused guide.",[129,1634,1636],{"id":1635},"faq","FAQ",[792,1638,1640],{"id":1639},"how-do-i-get-the-length-of-a-list-in-python","How do I get the length of a list in Python?",[20,1642,123,1643,1646],{},[15,1644,1645],{},"len(your_list)",". It returns the number of items in the list.",[792,1648,1650,1651,1654],{"id":1649},"what-does-len-return","What does ",[15,1652,1653],{},"len([])"," return?",[20,1656,1657,1658,1660],{},"It returns ",[15,1659,192],{}," because the list is empty.",[792,1662,1664],{"id":1663},"is-the-list-length-the-same-as-the-last-index","Is the list length the same as the last index?",[20,1666,1667],{},"No. The last index is one less than the length.",[792,1669,1671,1672,1674],{"id":1670},"can-i-use-my_listlen-in-python","Can I use ",[15,1673,798],{}," in Python?",[20,1676,1677,1678,1680,1681,1683],{},"No. Use ",[15,1679,166],{},", because ",[15,1682,25],{}," is a built-in function.",[129,1685,1687],{"id":1686},"see-also","See also",[134,1689,1690,1696,1701,1705,1709],{},[137,1691,1692],{},[282,1693,285,1694,288],{"href":284},[15,1695,25],{},[137,1697,1698],{},[282,1699,1700],{"href":1630},"How to get the length of a list in Python",[137,1702,1703],{},[282,1704,623],{"href":622},[137,1706,1707],{},[282,1708,1246],{"href":1245},[137,1710,1711],{},[282,1712,1713],{"href":1623},"How to loop through a list in Python",[1715,1716,1717],"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 .sP7_E{--shiki-light:#39ADB5;--shiki-default:#24292E;--shiki-dark:#E1E4E8}html pre.shiki code .srdBf, html code.shiki .srdBf{--shiki-light:#F76D47;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .sptTA, html code.shiki .sptTA{--shiki-light:#6182B8;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .slqww, html code.shiki .slqww{--shiki-light:#6182B8;--shiki-default:#24292E;--shiki-dark:#E1E4E8}html .light .shiki span {color: var(--shiki-light);background: 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