{"id":1657,"date":"2025-09-30T19:47:54","date_gmt":"2025-09-30T12:47:54","guid":{"rendered":"https:\/\/kienthucmo.com\/?p=1657"},"modified":"2025-11-05T23:44:25","modified_gmt":"2025-11-05T16:44:25","slug":"gioi-thieu-dictionary-va-cach-truy-cap-phan-tu-trong-python","status":"publish","type":"post","link":"https:\/\/kienthucmo.com\/vi\/gioi-thieu-dictionary-va-cach-truy-cap-phan-tu-trong-python\/","title":{"rendered":"Gi\u1edbi thi\u1ec7u Dictionary v\u00e0 c\u00e1ch truy c\u1eadp ph\u1ea7n t\u1eed trong Python"},"content":{"rendered":"\n

Trong qu\u00e1 tr\u00ecnh h\u1ecdc Python, m\u00ecnh nh\u1eadn ra c\u00f3 m\u1ed9t ki\u1ec3u d\u1eef li\u1ec7u c\u1ef1c k\u1ef3 h\u1eefu \u00edch m\u00e0 h\u1ea7u nh\u01b0 d\u1ef1 \u00e1n n\u00e0o c\u0169ng c\u1ea7n \u0111\u1ebfn, \u0111\u00f3 l\u00e0 Dictionary<\/strong>. N\u1ebfu nh\u01b0 list<\/code> gi\u00fap m\u00ecnh l\u01b0u tr\u1eef theo ch\u1ec9 s\u1ed1, th\u00ec dictionary cho ph\u00e9p m\u00ecnh l\u01b0u th\u00f4ng tin d\u01b0\u1edbi d\u1ea1ng c\u1eb7p key\u2013value<\/em> r\u1ea5t ti\u1ec7n \u0111\u1ec3 tra c\u1ee9u.<\/p>\n\n\n\n

B\u00e0i vi\u1ebft n\u00e0y m\u00ecnh mu\u1ed1n chia s\u1ebb l\u1ea1i nh\u1eefng g\u00ec m\u00ecnh \u0111\u00e3 t\u00ecm hi\u1ec3u v\u1ec1 dictionary: t\u1eeb kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n, c\u00e1ch t\u1ea1o, cho \u0111\u1ebfn c\u00e1c ph\u01b0\u01a1ng ph\u00e1p truy c\u1eadp ph\u1ea7n t\u1eed sao cho an to\u00e0n v\u00e0 hi\u1ec7u qu\u1ea3. M\u00ecnh s\u1ebd k\u00e8m theo nhi\u1ec1u v\u00ed d\u1ee5 th\u1ef1c t\u1ebf \u0111\u1ec3 b\u1ea1n d\u1ec5 h\u00ecnh dung, v\u00ec v\u1eady n\u1ebfu b\u1ea1n \u0111ang l\u00e0m quen v\u1edbi Python ho\u1eb7c mu\u1ed1n h\u1ec7 th\u1ed1ng l\u1ea1i ki\u1ebfn th\u1ee9c, th\u00ec b\u00e0i n\u00e0y ch\u1eafc ch\u1eafn s\u1ebd h\u1eefu \u00edch.<\/p>\n\n\n\n

1. Dictionary trong Python l\u00e0 g\u00ec?<\/h2>\n\n\n\n

Dictionary (vi\u1ebft t\u1eaft l\u00e0 dict<\/code>) l\u00e0 c\u1ea5u tr\u00fac d\u1eef li\u1ec7u l\u01b0u d\u1eef li\u1ec7u theo c\u1eb7p key\u2013value<\/strong>. M\u1ed7i ph\u1ea7n t\u1eed trong dictionary g\u1ed3m m\u1ed9t key<\/em> (kh\u00f3a) v\u00e0 m\u1ed9t value<\/em> (gi\u00e1 tr\u1ecb). Kh\u00e1c v\u1edbi list<\/code> hay tuple<\/code> d\u00f9ng ch\u1ec9 s\u1ed1 s\u1ed1 nguy\u00ean (index) \u0111\u1ec3 truy c\u1eadp, dictionary cho ph\u00e9p truy xu\u1ea5t tr\u1ef1c ti\u1ebfp b\u1eb1ng key \u2014 \u0111i\u1ec1u n\u00e0y r\u1ea5t h\u1eefu d\u1ee5ng khi b\u1ea1n mu\u1ed1n \u00e1nh x\u1ea1 (map) m\u1ed9t gi\u00e1 tr\u1ecb v\u1edbi m\u1ed9t kho\u00e1 c\u00f3 \u00fd ngh\u0129a.<\/p>\n\n\n\n

\u0110\u1eb7c \u0111i\u1ec3m ch\u00ednh:<\/strong><\/p>\n\n\n\n

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  • Key ph\u1ea3i l\u00e0 ki\u1ec3u b\u1ea5t bi\u1ebfn (immutable): string, number, tuple (v\u1edbi n\u1ed9i dung immutable)\u2026<\/li>\n\n\n\n
  • Value c\u00f3 th\u1ec3 l\u00e0 b\u1ea5t k\u1ef3 ki\u1ec3u d\u1eef li\u1ec7u n\u00e0o (list, dict kh\u00e1c, object\u2026).<\/li>\n\n\n\n
  • Dictionary l\u00e0 mutable: b\u1ea1n c\u00f3 th\u1ec3 th\u00eam, s\u1eeda, x\u00f3a ph\u1ea7n t\u1eed.<\/li>\n\n\n\n
  • Th\u1ee9 t\u1ef1 (order): t\u1eeb Python 3.7, dict gi\u1eef th\u1ee9 t\u1ef1 ch\u00e8n nh\u01b0ng b\u1ea1n kh\u00f4ng n\u00ean d\u1ef1a ho\u00e0n to\u00e0n v\u00e0o th\u1ee9 t\u1ef1 cho logic tra c\u1ee9u \u2014 dict ch\u1ee7 y\u1ebfu d\u00f9ng cho \u00e1nh x\u1ea1 nhanh.<\/li>\n<\/ul>\n\n\n\n

    2. C\u00e1ch t\u1ea1o Dictionary<\/h2>\n\n\n\n

    Python cung c\u1ea5p nhi\u1ec1u c\u00e1ch t\u1ea1o dict. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 c\u00e1c c\u00e1ch ph\u1ed5 bi\u1ebfn k\u00e8m v\u00ed d\u1ee5.<\/p>\n\n\n\n

    2.1. T\u1ea1o b\u1eb1ng literal {}<\/code><\/h3>\n\n\n\n
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