{"id":1621,"date":"2025-09-29T22:06:12","date_gmt":"2025-09-29T15:06:12","guid":{"rendered":"https:\/\/kienthucmo.com\/?p=1621"},"modified":"2025-11-05T23:43:48","modified_gmt":"2025-11-05T16:43:48","slug":"tong-hop-cac-ham-xu-ly-set-trong-python","status":"publish","type":"post","link":"https:\/\/kienthucmo.com\/vi\/tong-hop-cac-ham-xu-ly-set-trong-python\/","title":{"rendered":"T\u1ed5ng h\u1ee3p c\u00e1c h\u00e0m x\u1eed l\u00fd Set trong Python"},"content":{"rendered":"\n

Set l\u00e0 m\u1ed9t trong nh\u1eefng c\u1ea5u tr\u00fac d\u1eef li\u1ec7u r\u1ea5t h\u1eefu \u00edch trong Python: n\u00f3 l\u01b0u tr\u1eef c\u00e1c ph\u1ea7n t\u1eed kh\u00f4ng tr\u00f9ng l\u1eb7p<\/strong> v\u00e0 kh\u00f4ng c\u00f3 th\u1ee9 t\u1ef1<\/strong>. Nh\u1edd \u0111\u00f3 set th\u01b0\u1eddng d\u00f9ng \u0111\u1ec3 lo\u1ea1i b\u1ecf b\u1ea3n sao, ki\u1ec3m tra thu\u1ed9c t\u00ednh (membership) r\u1ea5t nhanh, v\u00e0 th\u1ef1c hi\u1ec7n c\u00e1c ph\u00e9p to\u00e1n t\u1eadp h\u1ee3p (h\u1ee3p, giao, hi\u1ec7u) m\u1ed9t c\u00e1ch tr\u1ef1c ti\u1ebfp.<\/p>\n\n\n\n

Trong b\u00e0i n\u00e0y m\u00ecnh s\u1ebd \u0111i t\u1eeb c\u01a1 b\u1ea3n \u0111\u1ebfn n\u00e2ng cao: c\u00e1ch t\u1ea1o set, th\u00eam\/x\u00f3a ph\u1ea7n t\u1eed, c\u00e1c ph\u00e9p to\u00e1n t\u1eadp h\u1ee3p (v\u1edbi c\u1ea3 ph\u01b0\u01a1ng th\u1ee9c v\u00e0 to\u00e1n t\u1eed), c\u00e1c ph\u01b0\u01a1ng th\u1ee9c in-place, hi\u1ec7u n\u0103ng\/\u0111\u1ed9 ph\u1ee9c t\u1ea1p, frozenset (phi\u00ean b\u1ea3n b\u1ea5t bi\u1ebfn), nh\u1eefng l\u01b0u \u00fd hay l\u1ed7i th\u01b0\u1eddng g\u1eb7p…<\/p>\n\n\n\n

B\u1ea3ng cheat-sheet \u2014 c\u00e1c ph\u01b0\u01a1ng th\u1ee9c v\u00e0 to\u00e1n t\u1eed quan tr\u1ecdng<\/h2>\n\n\n\n
Ph\u01b0\u01a1ng th\u1ee9c \/ To\u00e1n t\u1eed<\/th>Ch\u1ee9c n\u0103ng<\/th>Tr\u1ea3 v\u1ec1 \/ In-place<\/th>Complexity (avg)<\/th><\/tr><\/thead>
s.add(x)<\/code><\/td>Th\u00eam ph\u1ea7n t\u1eed x<\/td>In-place<\/td>O(1)<\/td><\/tr>
s.update(iter)<\/code><\/td>Th\u00eam nhi\u1ec1u ph\u1ea7n t\u1eed<\/td>In-place<\/td>O(k)<\/td><\/tr>
s.remove(x)<\/code><\/td>X\u00f3a x, KeyError n\u1ebfu kh\u00f4ng c\u00f3<\/td>In-place (exception)<\/td>O(1)<\/td><\/tr>
s.discard(x)<\/code><\/td>X\u00f3a x n\u1ebfu c\u00f3, kh\u00f4ng l\u1ed7i<\/td>In-place<\/td>O(1)<\/td><\/tr>
s.pop()<\/code><\/td>X\u00f3a v\u00e0 tr\u1ea3 v\u1ec1 1 ph\u1ea7n t\u1eed b\u1ea5t k\u1ef3<\/td>In-place<\/td>O(1)<\/td><\/tr>
s.clear()<\/code><\/td>X\u00f3a to\u00e0n b\u1ed9<\/td>In-place<\/td>O(1)<\/td><\/tr>
A.union(B)<\/code> \/ `A<\/td>B`<\/td>H\u1ee3p<\/td>New set<\/td><\/tr>
A.intersection(B)<\/code> \/ A & B<\/code><\/td>Giao<\/td>New set<\/td>O(min(len(A),len(B)))<\/td><\/tr>
A.difference(B)<\/code> \/ A - B<\/code><\/td>Hi\u1ec7u<\/td>New set<\/td>O(len(A))<\/td><\/tr>
A.symmetric_difference(B)<\/code> \/ A ^ B<\/code><\/td>Hi\u1ec7u \u0111\u1ed1i x\u1ee9ng<\/td>New set<\/td>O(len(A)+len(B))<\/td><\/tr>
A.update(B)<\/code> \/ `A<\/td>= B`<\/td>H\u1ee3p in-place<\/td>In-place<\/td><\/tr>
A.intersection_update(B)<\/code> \/ A &= B<\/code><\/td>Giao in-place<\/td>In-place<\/td>O(min(len(A),len(B)))<\/td><\/tr>
s.copy()<\/code><\/td>Sao ch\u00e9p shallow<\/td>New set<\/td>O(len(s))<\/td><\/tr>
frozenset(iter)<\/code><\/td>Set b\u1ea5t bi\u1ebfn<\/td>New frozenset<\/td>O(n)<\/td><\/tr>
x in s<\/code><\/td>Membership test<\/td>Bool<\/td>O(1)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

1. T\u1ea1o Set (kh\u1edfi t\u1ea1o)<\/h2>\n\n\n\n
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  • C\u00e1ch c\u01a1 b\u1ea3n: d\u00f9ng {}<\/code> v\u1edbi ph\u1ea7n t\u1eed ho\u1eb7c h\u00e0m set()<\/code> cho t\u1eadp r\u1ed7ng.<\/li>\n\n\n\n
  • Quan tr\u1ecdng:<\/strong> {}<\/code> t\u1ea1o dict r\u1ed7ng<\/strong>, do \u0111\u00f3 \u0111\u1ec3 t\u1ea1o set r\u1ed7ng ph\u1ea3i d\u00f9ng set()<\/code>.<\/li>\n<\/ul>\n\n\n\n
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