[{"data":1,"prerenderedAt":2089},["ShallowReactive",2],{"doc-\u002Freference\u002Fpython-set-update-method":3},{"id":4,"title":5,"body":6,"description":2082,"extension":2083,"meta":2084,"navigation":240,"path":2085,"seo":2086,"stem":2087,"__hash__":2088},"content\u002Freference\u002Fpython-set-update-method.md","Python Set update() Method",{"type":7,"value":8,"toc":2047},"minimark",[9,19,26,37,42,135,141,148,153,169,172,258,265,269,272,293,296,313,316,345,348,427,434,438,446,449,515,520,523,580,584,589,654,657,678,686,690,696,784,787,796,902,906,912,974,977,992,1009,1016,1078,1087,1090,1102,1107,1169,1173,1240,1243,1302,1312,1320,1323,1328,1338,1410,1414,1422,1513,1524,1528,1533,1537,1540,1603,1608,1665,1669,1672,1708,1718,1721,1775,1785,1789,1792,1857,1867,1873,1930,1934,1941,1946,1953,1956,1965,1973,1977,1982,1986,1993,1997,2034,2043],[10,11,13,14,18],"h1",{"id":12},"python-set-update-method","Python Set ",[15,16,17],"code",{},"update()"," Method",[20,21,22,25],"p",{},[15,23,24],{},"set.update()"," adds multiple items from another iterable into an existing set.",[20,27,28,29,36],{},"Use it when you want to change a set in place with values from a list, tuple, set, string, or another iterable. It is different from ",[30,31,33],"a",{"href":32},"\u002Freference\u002Fpython-set-add-method\u002F",[15,34,35],{},"set.add()",", which adds only one item.",[38,39,41],"h2",{"id":40},"quick-answer","Quick answer",[43,44,49],"pre",{"className":45,"code":46,"language":47,"meta":48,"style":48},"language-python shiki shiki-themes material-theme-lighter github-light github-dark","numbers = {1, 2}\nnumbers.update([2, 3, 4])\nprint(numbers)\n# {1, 2, 3, 4}\n","python","",[15,50,51,81,113,128],{"__ignoreMap":48},[52,53,56,60,64,68,72,75,78],"span",{"class":54,"line":55},"line",1,[52,57,59],{"class":58},"su5hD","numbers ",[52,61,63],{"class":62},"smGrS","=",[52,65,67],{"class":66},"sP7_E"," {",[52,69,71],{"class":70},"srdBf","1",[52,73,74],{"class":66},",",[52,76,77],{"class":70}," 2",[52,79,80],{"class":66},"}\n",[52,82,84,87,90,94,97,100,102,105,107,110],{"class":54,"line":83},2,[52,85,86],{"class":58},"numbers",[52,88,89],{"class":66},".",[52,91,93],{"class":92},"slqww","update",[52,95,96],{"class":66},"([",[52,98,99],{"class":70},"2",[52,101,74],{"class":66},[52,103,104],{"class":70}," 3",[52,106,74],{"class":66},[52,108,109],{"class":70}," 4",[52,111,112],{"class":66},"])\n",[52,114,116,120,123,125],{"class":54,"line":115},3,[52,117,119],{"class":118},"sptTA","print",[52,121,122],{"class":66},"(",[52,124,86],{"class":92},[52,126,127],{"class":66},")\n",[52,129,131],{"class":54,"line":130},4,[52,132,134],{"class":133},"sutJx","# {1, 2, 3, 4}\n",[20,136,137,138,140],{},"Use ",[15,139,17],{}," to add multiple items from a list, tuple, set, or other iterable into an existing set.",[38,142,144,145,147],{"id":143},"what-setupdate-does","What ",[15,146,24],{}," does",[20,149,150,152],{},[15,151,24],{},":",[154,155,156,160,163,166],"ul",{},[157,158,159],"li",{},"Adds items from another iterable into the current set",[157,161,162],{},"Changes the original set in place",[157,164,165],{},"Ignores duplicate values automatically",[157,167,168],{},"Does not return a new set",[20,170,171],{},"This means the set itself is modified.",[43,173,175],{"className":45,"code":174,"language":47,"meta":48,"style":48},"colors = {\"red\", \"blue\"}\ncolors.update([\"blue\", \"green\"])\n\nprint(colors)\n# {'red', 'blue', 'green'}\n",[15,176,177,208,236,242,252],{"__ignoreMap":48},[52,178,179,182,184,186,190,194,196,198,201,204,206],{"class":54,"line":55},[52,180,181],{"class":58},"colors ",[52,183,63],{"class":62},[52,185,67],{"class":66},[52,187,189],{"class":188},"sjJ54","\"",[52,191,193],{"class":192},"s_sjI","red",[52,195,189],{"class":188},[52,197,74],{"class":66},[52,199,200],{"class":188}," \"",[52,202,203],{"class":192},"blue",[52,205,189],{"class":188},[52,207,80],{"class":66},[52,209,210,213,215,217,219,221,223,225,227,229,232,234],{"class":54,"line":83},[52,211,212],{"class":58},"colors",[52,214,89],{"class":66},[52,216,93],{"class":92},[52,218,96],{"class":66},[52,220,189],{"class":188},[52,222,203],{"class":192},[52,224,189],{"class":188},[52,226,74],{"class":66},[52,228,200],{"class":188},[52,230,231],{"class":192},"green",[52,233,189],{"class":188},[52,235,112],{"class":66},[52,237,238],{"class":54,"line":115},[52,239,241],{"emptyLinePlaceholder":240},true,"\n",[52,243,244,246,248,250],{"class":54,"line":130},[52,245,119],{"class":118},[52,247,122],{"class":66},[52,249,212],{"class":92},[52,251,127],{"class":66},[52,253,255],{"class":54,"line":254},5,[52,256,257],{"class":133},"# {'red', 'blue', 'green'}\n",[20,259,260,261,264],{},"Even though ",[15,262,263],{},"\"blue\""," was added again, it appears only once because sets store unique values.",[38,266,268],{"id":267},"basic-syntax","Basic syntax",[20,270,271],{},"The basic syntax is:",[43,273,275],{"className":45,"code":274,"language":47,"meta":48,"style":48},"my_set.update(iterable)\n",[15,276,277],{"__ignoreMap":48},[52,278,279,282,284,286,288,291],{"class":54,"line":55},[52,280,281],{"class":58},"my_set",[52,283,89],{"class":66},[52,285,93],{"class":92},[52,287,122],{"class":66},[52,289,290],{"class":92},"iterable",[52,292,127],{"class":66},[20,294,295],{},"You can pass:",[154,297,298,301,304,307,310],{},[157,299,300],{},"A list",[157,302,303],{},"A tuple",[157,305,306],{},"Another set",[157,308,309],{},"A string",[157,311,312],{},"Any other iterable",[20,314,315],{},"You can also pass multiple iterables at once:",[43,317,319],{"className":45,"code":318,"language":47,"meta":48,"style":48},"my_set.update(a, b, c)\n",[15,320,321],{"__ignoreMap":48},[52,322,323,325,327,329,331,333,335,338,340,343],{"class":54,"line":55},[52,324,281],{"class":58},[52,326,89],{"class":66},[52,328,93],{"class":92},[52,330,122],{"class":66},[52,332,30],{"class":92},[52,334,74],{"class":66},[52,336,337],{"class":92}," b",[52,339,74],{"class":66},[52,341,342],{"class":92}," c",[52,344,127],{"class":66},[20,346,347],{},"Example:",[43,349,351],{"className":45,"code":350,"language":47,"meta":48,"style":48},"values = {1}\nvalues.update([2, 3], (4, 5), {6})\n\nprint(values)\n# {1, 2, 3, 4, 5, 6}\n",[15,352,353,366,408,412,422],{"__ignoreMap":48},[52,354,355,358,360,362,364],{"class":54,"line":55},[52,356,357],{"class":58},"values ",[52,359,63],{"class":62},[52,361,67],{"class":66},[52,363,71],{"class":70},[52,365,80],{"class":66},[52,367,368,371,373,375,377,379,381,383,386,389,392,394,397,400,402,405],{"class":54,"line":83},[52,369,370],{"class":58},"values",[52,372,89],{"class":66},[52,374,93],{"class":92},[52,376,96],{"class":66},[52,378,99],{"class":70},[52,380,74],{"class":66},[52,382,104],{"class":70},[52,384,385],{"class":66},"],",[52,387,388],{"class":66}," (",[52,390,391],{"class":70},"4",[52,393,74],{"class":66},[52,395,396],{"class":70}," 5",[52,398,399],{"class":66},"),",[52,401,67],{"class":66},[52,403,404],{"class":70},"6",[52,406,407],{"class":66},"})\n",[52,409,410],{"class":54,"line":115},[52,411,241],{"emptyLinePlaceholder":240},[52,413,414,416,418,420],{"class":54,"line":130},[52,415,119],{"class":118},[52,417,122],{"class":66},[52,419,370],{"class":92},[52,421,127],{"class":66},[52,423,424],{"class":54,"line":254},[52,425,426],{"class":133},"# {1, 2, 3, 4, 5, 6}\n",[20,428,429,430,89],{},"If you are new to sets, see ",[30,431,433],{"href":432},"\u002Freference\u002Fpython-set-creating-a-set\u002F","how to create a set in Python",[38,435,437],{"id":436},"what-it-returns","What it returns",[20,439,440,442,443,89],{},[15,441,24],{}," returns ",[15,444,445],{},"None",[20,447,448],{},"This is a very common beginner mistake:",[43,450,452],{"className":45,"code":451,"language":47,"meta":48,"style":48},"numbers = {1, 2}\nresult = numbers.update([3, 4])\n\nprint(result)\n# None\n",[15,453,454,470,495,499,510],{"__ignoreMap":48},[52,455,456,458,460,462,464,466,468],{"class":54,"line":55},[52,457,59],{"class":58},[52,459,63],{"class":62},[52,461,67],{"class":66},[52,463,71],{"class":70},[52,465,74],{"class":66},[52,467,77],{"class":70},[52,469,80],{"class":66},[52,471,472,475,477,480,482,484,486,489,491,493],{"class":54,"line":83},[52,473,474],{"class":58},"result ",[52,476,63],{"class":62},[52,478,479],{"class":58}," numbers",[52,481,89],{"class":66},[52,483,93],{"class":92},[52,485,96],{"class":66},[52,487,488],{"class":70},"3",[52,490,74],{"class":66},[52,492,109],{"class":70},[52,494,112],{"class":66},[52,496,497],{"class":54,"line":115},[52,498,241],{"emptyLinePlaceholder":240},[52,500,501,503,505,508],{"class":54,"line":130},[52,502,119],{"class":118},[52,504,122],{"class":66},[52,506,507],{"class":92},"result",[52,509,127],{"class":66},[52,511,512],{"class":54,"line":254},[52,513,514],{"class":133},"# None\n",[20,516,517,518,89],{},"The updated values are stored in the original set, not in ",[15,519,507],{},[20,521,522],{},"Correct usage:",[43,524,526],{"className":45,"code":525,"language":47,"meta":48,"style":48},"numbers = {1, 2}\nnumbers.update([3, 4])\n\nprint(numbers)\n# {1, 2, 3, 4}\n",[15,527,528,544,562,566,576],{"__ignoreMap":48},[52,529,530,532,534,536,538,540,542],{"class":54,"line":55},[52,531,59],{"class":58},[52,533,63],{"class":62},[52,535,67],{"class":66},[52,537,71],{"class":70},[52,539,74],{"class":66},[52,541,77],{"class":70},[52,543,80],{"class":66},[52,545,546,548,550,552,554,556,558,560],{"class":54,"line":83},[52,547,86],{"class":58},[52,549,89],{"class":66},[52,551,93],{"class":92},[52,553,96],{"class":66},[52,555,488],{"class":70},[52,557,74],{"class":66},[52,559,109],{"class":70},[52,561,112],{"class":66},[52,563,564],{"class":54,"line":115},[52,565,241],{"emptyLinePlaceholder":240},[52,567,568,570,572,574],{"class":54,"line":130},[52,569,119],{"class":118},[52,571,122],{"class":66},[52,573,86],{"class":92},[52,575,127],{"class":66},[52,577,578],{"class":54,"line":254},[52,579,134],{"class":133},[38,581,583],{"id":582},"example-update-with-a-list","Example: update with a list",[20,585,586,587,89],{},"A list is one of the most common things to pass to ",[15,588,17],{},[43,590,592],{"className":45,"code":591,"language":47,"meta":48,"style":48},"numbers = {1, 2}\nnumbers.update([2, 3, 4, 4])\n\nprint(numbers)\n# {1, 2, 3, 4}\n",[15,593,594,610,636,640,650],{"__ignoreMap":48},[52,595,596,598,600,602,604,606,608],{"class":54,"line":55},[52,597,59],{"class":58},[52,599,63],{"class":62},[52,601,67],{"class":66},[52,603,71],{"class":70},[52,605,74],{"class":66},[52,607,77],{"class":70},[52,609,80],{"class":66},[52,611,612,614,616,618,620,622,624,626,628,630,632,634],{"class":54,"line":83},[52,613,86],{"class":58},[52,615,89],{"class":66},[52,617,93],{"class":92},[52,619,96],{"class":66},[52,621,99],{"class":70},[52,623,74],{"class":66},[52,625,104],{"class":70},[52,627,74],{"class":66},[52,629,109],{"class":70},[52,631,74],{"class":66},[52,633,109],{"class":70},[52,635,112],{"class":66},[52,637,638],{"class":54,"line":115},[52,639,241],{"emptyLinePlaceholder":240},[52,641,642,644,646,648],{"class":54,"line":130},[52,643,119],{"class":118},[52,645,122],{"class":66},[52,647,86],{"class":92},[52,649,127],{"class":66},[52,651,652],{"class":54,"line":254},[52,653,134],{"class":133},[20,655,656],{},"What happens here:",[154,658,659,664,672],{},[157,660,661,663],{},[15,662,99],{}," is already in the set, so nothing changes for that value",[157,665,666,668,669,671],{},[15,667,488],{}," and ",[15,670,391],{}," are added",[157,673,674,675,677],{},"The second ",[15,676,391],{}," is ignored because sets do not keep duplicates",[20,679,680,681,685],{},"This is one reason sets are useful when you want unique values. For example, you can ",[30,682,684],{"href":683},"\u002Fhow-to\u002Fhow-to-remove-duplicates-from-a-list-in-python\u002F","remove duplicates from a list in Python"," by converting the list to a set.",[38,687,689],{"id":688},"example-update-with-another-set","Example: update with another set",[20,691,692,693,695],{},"You can use ",[15,694,17],{}," to combine values from one set into another.",[43,697,699],{"className":45,"code":698,"language":47,"meta":48,"style":48},"set_a = {1, 2, 3}\nset_b = {3, 4, 5}\n\nset_a.update(set_b)\n\nprint(set_a)\n# {1, 2, 3, 4, 5}\n",[15,700,701,722,743,747,763,767,778],{"__ignoreMap":48},[52,702,703,706,708,710,712,714,716,718,720],{"class":54,"line":55},[52,704,705],{"class":58},"set_a ",[52,707,63],{"class":62},[52,709,67],{"class":66},[52,711,71],{"class":70},[52,713,74],{"class":66},[52,715,77],{"class":70},[52,717,74],{"class":66},[52,719,104],{"class":70},[52,721,80],{"class":66},[52,723,724,727,729,731,733,735,737,739,741],{"class":54,"line":83},[52,725,726],{"class":58},"set_b ",[52,728,63],{"class":62},[52,730,67],{"class":66},[52,732,488],{"class":70},[52,734,74],{"class":66},[52,736,109],{"class":70},[52,738,74],{"class":66},[52,740,396],{"class":70},[52,742,80],{"class":66},[52,744,745],{"class":54,"line":115},[52,746,241],{"emptyLinePlaceholder":240},[52,748,749,752,754,756,758,761],{"class":54,"line":130},[52,750,751],{"class":58},"set_a",[52,753,89],{"class":66},[52,755,93],{"class":92},[52,757,122],{"class":66},[52,759,760],{"class":92},"set_b",[52,762,127],{"class":66},[52,764,765],{"class":54,"line":254},[52,766,241],{"emptyLinePlaceholder":240},[52,768,770,772,774,776],{"class":54,"line":769},6,[52,771,119],{"class":118},[52,773,122],{"class":66},[52,775,751],{"class":92},[52,777,127],{"class":66},[52,779,781],{"class":54,"line":780},7,[52,782,783],{"class":133},"# {1, 2, 3, 4, 5}\n",[20,785,786],{},"This is useful when you want to keep only unique values and modify the original set.",[20,788,789,790,89],{},"If you want a new combined set instead of changing the original, use ",[30,791,793],{"href":792},"\u002Freference\u002Fpython-set-union-method\u002F",[15,794,795],{},"set.union()",[43,797,799],{"className":45,"code":798,"language":47,"meta":48,"style":48},"set_a = {1, 2, 3}\nset_b = {3, 4, 5}\n\ncombined = set_a.union(set_b)\n\nprint(combined)\n# {1, 2, 3, 4, 5}\nprint(set_a)\n# {1, 2, 3}\n",[15,800,801,821,841,845,866,870,881,885,896],{"__ignoreMap":48},[52,802,803,805,807,809,811,813,815,817,819],{"class":54,"line":55},[52,804,705],{"class":58},[52,806,63],{"class":62},[52,808,67],{"class":66},[52,810,71],{"class":70},[52,812,74],{"class":66},[52,814,77],{"class":70},[52,816,74],{"class":66},[52,818,104],{"class":70},[52,820,80],{"class":66},[52,822,823,825,827,829,831,833,835,837,839],{"class":54,"line":83},[52,824,726],{"class":58},[52,826,63],{"class":62},[52,828,67],{"class":66},[52,830,488],{"class":70},[52,832,74],{"class":66},[52,834,109],{"class":70},[52,836,74],{"class":66},[52,838,396],{"class":70},[52,840,80],{"class":66},[52,842,843],{"class":54,"line":115},[52,844,241],{"emptyLinePlaceholder":240},[52,846,847,850,852,855,857,860,862,864],{"class":54,"line":130},[52,848,849],{"class":58},"combined ",[52,851,63],{"class":62},[52,853,854],{"class":58}," set_a",[52,856,89],{"class":66},[52,858,859],{"class":92},"union",[52,861,122],{"class":66},[52,863,760],{"class":92},[52,865,127],{"class":66},[52,867,868],{"class":54,"line":254},[52,869,241],{"emptyLinePlaceholder":240},[52,871,872,874,876,879],{"class":54,"line":769},[52,873,119],{"class":118},[52,875,122],{"class":66},[52,877,878],{"class":92},"combined",[52,880,127],{"class":66},[52,882,883],{"class":54,"line":780},[52,884,783],{"class":133},[52,886,888,890,892,894],{"class":54,"line":887},8,[52,889,119],{"class":118},[52,891,122],{"class":66},[52,893,751],{"class":92},[52,895,127],{"class":66},[52,897,899],{"class":54,"line":898},9,[52,900,901],{"class":133},"# {1, 2, 3}\n",[38,903,905],{"id":904},"example-update-with-a-string","Example: update with a string",[20,907,908,909,911],{},"A string is iterable, so ",[15,910,17],{}," adds each character separately.",[43,913,915],{"className":45,"code":914,"language":47,"meta":48,"style":48},"letters = {\"x\"}\nletters.update(\"cat\")\n\nprint(letters)\n# {'x', 'c', 'a', 't'}\n",[15,916,917,935,955,959,969],{"__ignoreMap":48},[52,918,919,922,924,926,928,931,933],{"class":54,"line":55},[52,920,921],{"class":58},"letters ",[52,923,63],{"class":62},[52,925,67],{"class":66},[52,927,189],{"class":188},[52,929,930],{"class":192},"x",[52,932,189],{"class":188},[52,934,80],{"class":66},[52,936,937,940,942,944,946,948,951,953],{"class":54,"line":83},[52,938,939],{"class":58},"letters",[52,941,89],{"class":66},[52,943,93],{"class":92},[52,945,122],{"class":66},[52,947,189],{"class":188},[52,949,950],{"class":192},"cat",[52,952,189],{"class":188},[52,954,127],{"class":66},[52,956,957],{"class":54,"line":115},[52,958,241],{"emptyLinePlaceholder":240},[52,960,961,963,965,967],{"class":54,"line":130},[52,962,119],{"class":118},[52,964,122],{"class":66},[52,966,939],{"class":92},[52,968,127],{"class":66},[52,970,971],{"class":54,"line":254},[52,972,973],{"class":133},"# {'x', 'c', 'a', 't'}\n",[20,975,976],{},"This often surprises beginners.",[20,978,979,982,983,987,988,991],{},[15,980,981],{},"update(\"cat\")"," does ",[984,985,986],"strong",{},"not"," add ",[15,989,990],{},"\"cat\""," as one item. It adds:",[154,993,994,999,1004],{},[157,995,996],{},[15,997,998],{},"\"c\"",[157,1000,1001],{},[15,1002,1003],{},"\"a\"",[157,1005,1006],{},[15,1007,1008],{},"\"t\"",[20,1010,1011,1012,152],{},"If you want to add one whole value, use ",[30,1013,1014],{"href":32},[15,1015,35],{},[43,1017,1019],{"className":45,"code":1018,"language":47,"meta":48,"style":48},"words = {\"dog\"}\nwords.add(\"cat\")\n\nprint(words)\n# {'dog', 'cat'}\n",[15,1020,1021,1039,1059,1063,1073],{"__ignoreMap":48},[52,1022,1023,1026,1028,1030,1032,1035,1037],{"class":54,"line":55},[52,1024,1025],{"class":58},"words ",[52,1027,63],{"class":62},[52,1029,67],{"class":66},[52,1031,189],{"class":188},[52,1033,1034],{"class":192},"dog",[52,1036,189],{"class":188},[52,1038,80],{"class":66},[52,1040,1041,1044,1046,1049,1051,1053,1055,1057],{"class":54,"line":83},[52,1042,1043],{"class":58},"words",[52,1045,89],{"class":66},[52,1047,1048],{"class":92},"add",[52,1050,122],{"class":66},[52,1052,189],{"class":188},[52,1054,950],{"class":192},[52,1056,189],{"class":188},[52,1058,127],{"class":66},[52,1060,1061],{"class":54,"line":115},[52,1062,241],{"emptyLinePlaceholder":240},[52,1064,1065,1067,1069,1071],{"class":54,"line":130},[52,1066,119],{"class":118},[52,1068,122],{"class":66},[52,1070,1043],{"class":92},[52,1072,127],{"class":66},[52,1074,1075],{"class":54,"line":254},[52,1076,1077],{"class":133},"# {'dog', 'cat'}\n",[38,1079,1081,1083,1084],{"id":1080},"update-vs-add",[15,1082,17],{}," vs ",[15,1085,1086],{},"add()",[20,1088,1089],{},"The difference is simple:",[154,1091,1092,1097],{},[157,1093,1094,1096],{},[15,1095,1086],{}," adds one item",[157,1098,1099,1101],{},[15,1100,17],{}," adds multiple items from an iterable",[20,1103,1104,1105,152],{},"Example with ",[15,1106,1086],{},[43,1108,1110],{"className":45,"code":1109,"language":47,"meta":48,"style":48},"fruits = {\"apple\"}\nfruits.add(\"banana\")\n\nprint(fruits)\n# {'apple', 'banana'}\n",[15,1111,1112,1130,1150,1154,1164],{"__ignoreMap":48},[52,1113,1114,1117,1119,1121,1123,1126,1128],{"class":54,"line":55},[52,1115,1116],{"class":58},"fruits ",[52,1118,63],{"class":62},[52,1120,67],{"class":66},[52,1122,189],{"class":188},[52,1124,1125],{"class":192},"apple",[52,1127,189],{"class":188},[52,1129,80],{"class":66},[52,1131,1132,1135,1137,1139,1141,1143,1146,1148],{"class":54,"line":83},[52,1133,1134],{"class":58},"fruits",[52,1136,89],{"class":66},[52,1138,1048],{"class":92},[52,1140,122],{"class":66},[52,1142,189],{"class":188},[52,1144,1145],{"class":192},"banana",[52,1147,189],{"class":188},[52,1149,127],{"class":66},[52,1151,1152],{"class":54,"line":115},[52,1153,241],{"emptyLinePlaceholder":240},[52,1155,1156,1158,1160,1162],{"class":54,"line":130},[52,1157,119],{"class":118},[52,1159,122],{"class":66},[52,1161,1134],{"class":92},[52,1163,127],{"class":66},[52,1165,1166],{"class":54,"line":254},[52,1167,1168],{"class":133},"# {'apple', 'banana'}\n",[20,1170,1104,1171,152],{},[15,1172,17],{},[43,1174,1176],{"className":45,"code":1175,"language":47,"meta":48,"style":48},"fruits = {\"apple\"}\nfruits.update([\"banana\", \"orange\"])\n\nprint(fruits)\n# {'apple', 'banana', 'orange'}\n",[15,1177,1178,1194,1221,1225,1235],{"__ignoreMap":48},[52,1179,1180,1182,1184,1186,1188,1190,1192],{"class":54,"line":55},[52,1181,1116],{"class":58},[52,1183,63],{"class":62},[52,1185,67],{"class":66},[52,1187,189],{"class":188},[52,1189,1125],{"class":192},[52,1191,189],{"class":188},[52,1193,80],{"class":66},[52,1195,1196,1198,1200,1202,1204,1206,1208,1210,1212,1214,1217,1219],{"class":54,"line":83},[52,1197,1134],{"class":58},[52,1199,89],{"class":66},[52,1201,93],{"class":92},[52,1203,96],{"class":66},[52,1205,189],{"class":188},[52,1207,1145],{"class":192},[52,1209,189],{"class":188},[52,1211,74],{"class":66},[52,1213,200],{"class":188},[52,1215,1216],{"class":192},"orange",[52,1218,189],{"class":188},[52,1220,112],{"class":66},[52,1222,1223],{"class":54,"line":115},[52,1224,241],{"emptyLinePlaceholder":240},[52,1226,1227,1229,1231,1233],{"class":54,"line":130},[52,1228,119],{"class":118},[52,1230,122],{"class":66},[52,1232,1134],{"class":92},[52,1234,127],{"class":66},[52,1236,1237],{"class":54,"line":254},[52,1238,1239],{"class":133},"# {'apple', 'banana', 'orange'}\n",[20,1241,1242],{},"Important warning with strings:",[43,1244,1246],{"className":45,"code":1245,"language":47,"meta":48,"style":48},"fruits = {\"apple\"}\nfruits.update(\"kiwi\")\n\nprint(fruits)\n# Adds 'k', 'i', 'w', 'i' as characters\n",[15,1247,1248,1264,1283,1287,1297],{"__ignoreMap":48},[52,1249,1250,1252,1254,1256,1258,1260,1262],{"class":54,"line":55},[52,1251,1116],{"class":58},[52,1253,63],{"class":62},[52,1255,67],{"class":66},[52,1257,189],{"class":188},[52,1259,1125],{"class":192},[52,1261,189],{"class":188},[52,1263,80],{"class":66},[52,1265,1266,1268,1270,1272,1274,1276,1279,1281],{"class":54,"line":83},[52,1267,1134],{"class":58},[52,1269,89],{"class":66},[52,1271,93],{"class":92},[52,1273,122],{"class":66},[52,1275,189],{"class":188},[52,1277,1278],{"class":192},"kiwi",[52,1280,189],{"class":188},[52,1282,127],{"class":66},[52,1284,1285],{"class":54,"line":115},[52,1286,241],{"emptyLinePlaceholder":240},[52,1288,1289,1291,1293,1295],{"class":54,"line":130},[52,1290,119],{"class":118},[52,1292,122],{"class":66},[52,1294,1134],{"class":92},[52,1296,127],{"class":66},[52,1298,1299],{"class":54,"line":254},[52,1300,1301],{"class":133},"# Adds 'k', 'i', 'w', 'i' as characters\n",[20,1303,1304,1305,1308,1309,1311],{},"If you wanted ",[15,1306,1307],{},"\"kiwi\""," as one item, use ",[15,1310,1086],{}," instead.",[38,1313,1315,1083,1317],{"id":1314},"update-vs-union",[15,1316,17],{},[15,1318,1319],{},"union()",[20,1321,1322],{},"Both can combine values, but they work differently.",[1324,1325,1326],"h3",{"id":93},[15,1327,17],{},[154,1329,1330,1333],{},[157,1331,1332],{},"Changes the existing set",[157,1334,1335,1336],{},"Returns ",[15,1337,445],{},[43,1339,1341],{"className":45,"code":1340,"language":47,"meta":48,"style":48},"a = {1, 2}\nb = {2, 3}\n\na.update(b)\nprint(a)\n# {1, 2, 3}\n",[15,1342,1343,1360,1377,1381,1396,1406],{"__ignoreMap":48},[52,1344,1345,1348,1350,1352,1354,1356,1358],{"class":54,"line":55},[52,1346,1347],{"class":58},"a ",[52,1349,63],{"class":62},[52,1351,67],{"class":66},[52,1353,71],{"class":70},[52,1355,74],{"class":66},[52,1357,77],{"class":70},[52,1359,80],{"class":66},[52,1361,1362,1365,1367,1369,1371,1373,1375],{"class":54,"line":83},[52,1363,1364],{"class":58},"b ",[52,1366,63],{"class":62},[52,1368,67],{"class":66},[52,1370,99],{"class":70},[52,1372,74],{"class":66},[52,1374,104],{"class":70},[52,1376,80],{"class":66},[52,1378,1379],{"class":54,"line":115},[52,1380,241],{"emptyLinePlaceholder":240},[52,1382,1383,1385,1387,1389,1391,1394],{"class":54,"line":130},[52,1384,30],{"class":58},[52,1386,89],{"class":66},[52,1388,93],{"class":92},[52,1390,122],{"class":66},[52,1392,1393],{"class":92},"b",[52,1395,127],{"class":66},[52,1397,1398,1400,1402,1404],{"class":54,"line":254},[52,1399,119],{"class":118},[52,1401,122],{"class":66},[52,1403,30],{"class":92},[52,1405,127],{"class":66},[52,1407,1408],{"class":54,"line":769},[52,1409,901],{"class":133},[1324,1411,1412],{"id":859},[15,1413,1319],{},[154,1415,1416,1419],{},[157,1417,1418],{},"Returns a new set",[157,1420,1421],{},"Does not change the original set",[43,1423,1425],{"className":45,"code":1424,"language":47,"meta":48,"style":48},"a = {1, 2}\nb = {2, 3}\n\nc = a.union(b)\nprint(c)\n# {1, 2, 3}\nprint(a)\n# {1, 2}\n",[15,1426,1427,1443,1459,1463,1483,1494,1498,1508],{"__ignoreMap":48},[52,1428,1429,1431,1433,1435,1437,1439,1441],{"class":54,"line":55},[52,1430,1347],{"class":58},[52,1432,63],{"class":62},[52,1434,67],{"class":66},[52,1436,71],{"class":70},[52,1438,74],{"class":66},[52,1440,77],{"class":70},[52,1442,80],{"class":66},[52,1444,1445,1447,1449,1451,1453,1455,1457],{"class":54,"line":83},[52,1446,1364],{"class":58},[52,1448,63],{"class":62},[52,1450,67],{"class":66},[52,1452,99],{"class":70},[52,1454,74],{"class":66},[52,1456,104],{"class":70},[52,1458,80],{"class":66},[52,1460,1461],{"class":54,"line":115},[52,1462,241],{"emptyLinePlaceholder":240},[52,1464,1465,1468,1470,1473,1475,1477,1479,1481],{"class":54,"line":130},[52,1466,1467],{"class":58},"c ",[52,1469,63],{"class":62},[52,1471,1472],{"class":58}," a",[52,1474,89],{"class":66},[52,1476,859],{"class":92},[52,1478,122],{"class":66},[52,1480,1393],{"class":92},[52,1482,127],{"class":66},[52,1484,1485,1487,1489,1492],{"class":54,"line":254},[52,1486,119],{"class":118},[52,1488,122],{"class":66},[52,1490,1491],{"class":92},"c",[52,1493,127],{"class":66},[52,1495,1496],{"class":54,"line":769},[52,1497,901],{"class":133},[52,1499,1500,1502,1504,1506],{"class":54,"line":780},[52,1501,119],{"class":118},[52,1503,122],{"class":66},[52,1505,30],{"class":92},[52,1507,127],{"class":66},[52,1509,1510],{"class":54,"line":887},[52,1511,1512],{"class":133},"# {1, 2}\n",[20,1514,1515,1516,1518,1519,1523],{},"Choose ",[15,1517,17],{}," when you want to modify the original set in place. Choose ",[30,1520,1521],{"href":792},[15,1522,1319],{}," when you want a new set.",[38,1525,1527],{"id":1526},"common-errors-and-confusion","Common errors and confusion",[20,1529,1530,1531,89],{},"Here are the most common problems beginners run into with ",[15,1532,24],{},[1324,1534,1536],{"id":1535},"_1-saving-the-return-value","1. Saving the return value",[20,1538,1539],{},"This is wrong if you expect a set back:",[43,1541,1543],{"className":45,"code":1542,"language":47,"meta":48,"style":48},"my_set = {1, 2}\nresult = my_set.update([3, 4])\n\nprint(result)\n# None\n",[15,1544,1545,1562,1585,1589,1599],{"__ignoreMap":48},[52,1546,1547,1550,1552,1554,1556,1558,1560],{"class":54,"line":55},[52,1548,1549],{"class":58},"my_set ",[52,1551,63],{"class":62},[52,1553,67],{"class":66},[52,1555,71],{"class":70},[52,1557,74],{"class":66},[52,1559,77],{"class":70},[52,1561,80],{"class":66},[52,1563,1564,1566,1568,1571,1573,1575,1577,1579,1581,1583],{"class":54,"line":83},[52,1565,474],{"class":58},[52,1567,63],{"class":62},[52,1569,1570],{"class":58}," my_set",[52,1572,89],{"class":66},[52,1574,93],{"class":92},[52,1576,96],{"class":66},[52,1578,488],{"class":70},[52,1580,74],{"class":66},[52,1582,109],{"class":70},[52,1584,112],{"class":66},[52,1586,1587],{"class":54,"line":115},[52,1588,241],{"emptyLinePlaceholder":240},[52,1590,1591,1593,1595,1597],{"class":54,"line":130},[52,1592,119],{"class":118},[52,1594,122],{"class":66},[52,1596,507],{"class":92},[52,1598,127],{"class":66},[52,1600,1601],{"class":54,"line":254},[52,1602,514],{"class":133},[20,1604,1605,1606,152],{},"Use the original set after calling ",[15,1607,17],{},[43,1609,1611],{"className":45,"code":1610,"language":47,"meta":48,"style":48},"my_set = {1, 2}\nmy_set.update([3, 4])\n\nprint(my_set)\n# {1, 2, 3, 4}\n",[15,1612,1613,1629,1647,1651,1661],{"__ignoreMap":48},[52,1614,1615,1617,1619,1621,1623,1625,1627],{"class":54,"line":55},[52,1616,1549],{"class":58},[52,1618,63],{"class":62},[52,1620,67],{"class":66},[52,1622,71],{"class":70},[52,1624,74],{"class":66},[52,1626,77],{"class":70},[52,1628,80],{"class":66},[52,1630,1631,1633,1635,1637,1639,1641,1643,1645],{"class":54,"line":83},[52,1632,281],{"class":58},[52,1634,89],{"class":66},[52,1636,93],{"class":92},[52,1638,96],{"class":66},[52,1640,488],{"class":70},[52,1642,74],{"class":66},[52,1644,109],{"class":70},[52,1646,112],{"class":66},[52,1648,1649],{"class":54,"line":115},[52,1650,241],{"emptyLinePlaceholder":240},[52,1652,1653,1655,1657,1659],{"class":54,"line":130},[52,1654,119],{"class":118},[52,1656,122],{"class":66},[52,1658,281],{"class":92},[52,1660,127],{"class":66},[52,1662,1663],{"class":54,"line":254},[52,1664,134],{"class":133},[1324,1666,1668],{"id":1667},"_2-passing-a-non-iterable","2. Passing a non-iterable",[20,1670,1671],{},"This causes an error:",[43,1673,1675],{"className":45,"code":1674,"language":47,"meta":48,"style":48},"my_set = {1, 2}\nmy_set.update(5)\n",[15,1676,1677,1693],{"__ignoreMap":48},[52,1678,1679,1681,1683,1685,1687,1689,1691],{"class":54,"line":55},[52,1680,1549],{"class":58},[52,1682,63],{"class":62},[52,1684,67],{"class":66},[52,1686,71],{"class":70},[52,1688,74],{"class":66},[52,1690,77],{"class":70},[52,1692,80],{"class":66},[52,1694,1695,1697,1699,1701,1703,1706],{"class":54,"line":83},[52,1696,281],{"class":58},[52,1698,89],{"class":66},[52,1700,93],{"class":92},[52,1702,122],{"class":66},[52,1704,1705],{"class":70},"5",[52,1707,127],{"class":66},[20,1709,1710,1711,1714,1715,1717],{},"You will get a ",[15,1712,1713],{},"TypeError"," because ",[15,1716,1705],{}," is an integer, not an iterable.",[20,1719,1720],{},"Use an iterable instead:",[43,1722,1724],{"className":45,"code":1723,"language":47,"meta":48,"style":48},"my_set = {1, 2}\nmy_set.update([5])\n\nprint(my_set)\n# {1, 2, 5}\n",[15,1725,1726,1742,1756,1760,1770],{"__ignoreMap":48},[52,1727,1728,1730,1732,1734,1736,1738,1740],{"class":54,"line":55},[52,1729,1549],{"class":58},[52,1731,63],{"class":62},[52,1733,67],{"class":66},[52,1735,71],{"class":70},[52,1737,74],{"class":66},[52,1739,77],{"class":70},[52,1741,80],{"class":66},[52,1743,1744,1746,1748,1750,1752,1754],{"class":54,"line":83},[52,1745,281],{"class":58},[52,1747,89],{"class":66},[52,1749,93],{"class":92},[52,1751,96],{"class":66},[52,1753,1705],{"class":70},[52,1755,112],{"class":66},[52,1757,1758],{"class":54,"line":115},[52,1759,241],{"emptyLinePlaceholder":240},[52,1761,1762,1764,1766,1768],{"class":54,"line":130},[52,1763,119],{"class":118},[52,1765,122],{"class":66},[52,1767,281],{"class":92},[52,1769,127],{"class":66},[52,1771,1772],{"class":54,"line":254},[52,1773,1774],{"class":133},"# {1, 2, 5}\n",[20,1776,1777,1778,89],{},"If you see this problem, read ",[30,1779,1781,1782],{"href":1780},"\u002Ferrors\u002Ftypeerror-int-object-is-not-iterable-fix\u002F","how to fix ",[15,1783,1784],{},"TypeError: 'int' object is not iterable",[1324,1786,1788],{"id":1787},"_3-expecting-duplicates-to-stay","3. Expecting duplicates to stay",[20,1790,1791],{},"Sets only keep unique values.",[43,1793,1795],{"className":45,"code":1794,"language":47,"meta":48,"style":48},"my_set = {1, 2}\nmy_set.update([2, 2, 2, 3])\n\nprint(my_set)\n# {1, 2, 3}\n",[15,1796,1797,1813,1839,1843,1853],{"__ignoreMap":48},[52,1798,1799,1801,1803,1805,1807,1809,1811],{"class":54,"line":55},[52,1800,1549],{"class":58},[52,1802,63],{"class":62},[52,1804,67],{"class":66},[52,1806,71],{"class":70},[52,1808,74],{"class":66},[52,1810,77],{"class":70},[52,1812,80],{"class":66},[52,1814,1815,1817,1819,1821,1823,1825,1827,1829,1831,1833,1835,1837],{"class":54,"line":83},[52,1816,281],{"class":58},[52,1818,89],{"class":66},[52,1820,93],{"class":92},[52,1822,96],{"class":66},[52,1824,99],{"class":70},[52,1826,74],{"class":66},[52,1828,77],{"class":70},[52,1830,74],{"class":66},[52,1832,77],{"class":70},[52,1834,74],{"class":66},[52,1836,104],{"class":70},[52,1838,112],{"class":66},[52,1840,1841],{"class":54,"line":115},[52,1842,241],{"emptyLinePlaceholder":240},[52,1844,1845,1847,1849,1851],{"class":54,"line":130},[52,1846,119],{"class":118},[52,1848,122],{"class":66},[52,1850,281],{"class":92},[52,1852,127],{"class":66},[52,1854,1855],{"class":54,"line":254},[52,1856,901],{"class":133},[1324,1858,1860,1861,1863,1864,1866],{"id":1859},"_4-using-update-when-add-is-better","4. Using ",[15,1862,17],{}," when ",[15,1865,1086],{}," is better",[20,1868,1869,1870,1872],{},"If you want to add one single value, especially a string, ",[15,1871,1086],{}," is usually the better choice.",[43,1874,1876],{"className":45,"code":1875,"language":47,"meta":48,"style":48},"my_set = {\"dog\"}\nmy_set.add(\"cat\")\n\nprint(my_set)\n# {'dog', 'cat'}\n",[15,1877,1878,1894,1912,1916,1926],{"__ignoreMap":48},[52,1879,1880,1882,1884,1886,1888,1890,1892],{"class":54,"line":55},[52,1881,1549],{"class":58},[52,1883,63],{"class":62},[52,1885,67],{"class":66},[52,1887,189],{"class":188},[52,1889,1034],{"class":192},[52,1891,189],{"class":188},[52,1893,80],{"class":66},[52,1895,1896,1898,1900,1902,1904,1906,1908,1910],{"class":54,"line":83},[52,1897,281],{"class":58},[52,1899,89],{"class":66},[52,1901,1048],{"class":92},[52,1903,122],{"class":66},[52,1905,189],{"class":188},[52,1907,950],{"class":192},[52,1909,189],{"class":188},[52,1911,127],{"class":66},[52,1913,1914],{"class":54,"line":115},[52,1915,241],{"emptyLinePlaceholder":240},[52,1917,1918,1920,1922,1924],{"class":54,"line":130},[52,1919,119],{"class":118},[52,1921,122],{"class":66},[52,1923,281],{"class":92},[52,1925,127],{"class":66},[52,1927,1928],{"class":54,"line":254},[52,1929,1077],{"class":133},[38,1931,1933],{"id":1932},"faq","FAQ",[1324,1935,1937,1938,1940],{"id":1936},"does-setupdate-return-a-new-set","Does ",[15,1939,24],{}," return a new set?",[20,1942,1943,1944,89],{},"No. It changes the existing set and returns ",[15,1945,445],{},[1324,1947,1949,1950,1952],{"id":1948},"can-i-use-update-with-a-list","Can I use ",[15,1951,17],{}," with a list?",[20,1954,1955],{},"Yes. Any iterable like a list, tuple, set, or string can be used.",[1324,1957,1959,1960,668,1962,1964],{"id":1958},"what-is-the-difference-between-add-and-update","What is the difference between ",[15,1961,1086],{},[15,1963,17],{},"?",[20,1966,1967,1969,1970,1972],{},[15,1968,1086],{}," adds one item. ",[15,1971,17],{}," adds multiple items from an iterable.",[1324,1974,1976],{"id":1975},"why-did-my-string-get-split-into-letters","Why did my string get split into letters?",[20,1978,1979,1980,911],{},"Because strings are iterable, so ",[15,1981,17],{},[1324,1983,1985],{"id":1984},"how-do-i-combine-two-sets-without-changing-the-original","How do I combine two sets without changing the original?",[20,1987,137,1988,1990,1991,89],{},[15,1989,1319],{}," instead of ",[15,1992,17],{},[38,1994,1996],{"id":1995},"see-also","See also",[154,1998,1999,2006,2013,2020,2027],{},[157,2000,2001],{},[30,2002,2003],{"href":32},[15,2004,2005],{},"Python set add() method",[157,2007,2008],{},[30,2009,2010],{"href":792},[15,2011,2012],{},"Python set union() method",[157,2014,2015],{},[30,2016,2017],{"href":432},[15,2018,2019],{},"How to create a set in Python",[157,2021,2022],{},[30,2023,2024],{"href":683},[15,2025,2026],{},"How to remove duplicates from a list in Python",[157,2028,2029],{},[30,2030,2031,2033],{"href":1780},[15,2032,1784],{}," fix",[20,2035,2036,2037,2039,2040,2042],{},"Next, learn when to use ",[15,2038,35],{}," for a single value and ",[15,2041,795],{}," when you want a new combined set without changing the original.",[2044,2045,2046],"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 .slqww, html code.shiki .slqww{--shiki-light:#6182B8;--shiki-default:#24292E;--shiki-dark:#E1E4E8}html pre.shiki code .sptTA, html code.shiki .sptTA{--shiki-light:#6182B8;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .sutJx, html code.shiki .sutJx{--shiki-light:#90A4AE;--shiki-light-font-style:italic;--shiki-default:#6A737D;--shiki-default-font-style:inherit;--shiki-dark:#6A737D;--shiki-dark-font-style:inherit}html .light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html.light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html pre.shiki code .sjJ54, html code.shiki .sjJ54{--shiki-light:#39ADB5;--shiki-default:#032F62;--shiki-dark:#9ECBFF}html pre.shiki code .s_sjI, html code.shiki .s_sjI{--shiki-light:#91B859;--shiki-default:#032F62;--shiki-dark:#9ECBFF}",{"title":48,"searchDepth":83,"depth":83,"links":2048},[2049,2050,2052,2053,2054,2055,2056,2057,2059,2064,2071,2081],{"id":40,"depth":83,"text":41},{"id":143,"depth":83,"text":2051},"What set.update() does",{"id":267,"depth":83,"text":268},{"id":436,"depth":83,"text":437},{"id":582,"depth":83,"text":583},{"id":688,"depth":83,"text":689},{"id":904,"depth":83,"text":905},{"id":1080,"depth":83,"text":2058},"update() vs add()",{"id":1314,"depth":83,"text":2060,"children":2061},"update() vs union()",[2062,2063],{"id":93,"depth":115,"text":17},{"id":859,"depth":115,"text":1319},{"id":1526,"depth":83,"text":1527,"children":2065},[2066,2067,2068,2069],{"id":1535,"depth":115,"text":1536},{"id":1667,"depth":115,"text":1668},{"id":1787,"depth":115,"text":1788},{"id":1859,"depth":115,"text":2070},"4. Using update() when add() is better",{"id":1932,"depth":83,"text":1933,"children":2072},[2073,2075,2077,2079,2080],{"id":1936,"depth":115,"text":2074},"Does set.update() return a new set?",{"id":1948,"depth":115,"text":2076},"Can I use update() with a list?",{"id":1958,"depth":115,"text":2078},"What is the difference between add() and update()?",{"id":1975,"depth":115,"text":1976},{"id":1984,"depth":115,"text":1985},{"id":1995,"depth":83,"text":1996},"Master python set update method in our comprehensive Python beginner guide.","md",{},"\u002Freference\u002Fpython-set-update-method",{"title":5,"description":2082},"reference\u002Fpython-set-update-method","O92kX80vUFExg-dtCXumAvm7IuzEHXgSTW4bzDeyLc8",1777585515214]