{"id":353,"date":"2024-06-23T17:16:02","date_gmt":"2024-06-23T09:16:02","guid":{"rendered":"https:\/\/cococat.top\/?p=353"},"modified":"2024-06-23T17:16:02","modified_gmt":"2024-06-23T09:16:02","slug":"rust-note-4-strings","status":"publish","type":"post","link":"https:\/\/cococat.top\/index.php\/2024\/06\/23\/rust-note-4-strings\/","title":{"rendered":"rust \u7b14\u8bb0 4\uff1a\u5f7b\u5e95\u641e\u6e05\u695a\u5404\u79cd\u5b57\u7b26\u4e32"},"content":{"rendered":"

1. String<\/code>, &str<\/code> \u548c str<\/code><\/h2>\n

\u60f3\u8981\u641e\u6e05\u695a\u8fd9\u4e09\u8005\u7684\u5dee\u522b\uff0c\u8981\u4ece str<\/code> \u5f00\u59cb\u8bf4\u8d77\u3002<\/p>\n

1.1. str<\/code> \u548c &str<\/code><\/h3>\n

str<\/code> \u662f\u5b57\u7b26\u4e32\u5207\u7247\uff08string slice\uff09\uff0c\u662f\u5bf9\u90e8\u5206\u8fde\u7eed\u7684 UTF8 \u5b57\u7b26\u5e8f\u5217\u7684\u5f15\u7528\u3002<\/p>\n

\u6240\u6709\u7684\u5207\u7247\u7c7b\u578b\uff0c\u4f8b\u5982 str<\/code>\u3001[u8]<\/code>\u3001[i32]<\/code> \uff0c\u90fd\u662f Unsized \u7684\uff08\u4e0d\u5b9a\u957f\u7c7b\u578b\uff0c\u6216\u79f0\u52a8\u6001\u5927\u5c0f\u7c7b\u578b\uff0cDynamicly Sized Types, DST\uff09\uff0c\u5b83\u4eec\u5360\u7528\u7684\u5185\u5b58\u7a7a\u95f4\u7684\u5177\u4f53\u5927\u5c0f\u5728\u7f16\u8bd1\u671f\u662f\u4e0d\u53ef\u77e5\u7684\u3002<\/p>\n

\u6211\u4eec\u77e5\u9053\uff0c\u53d8\u91cf\u90fd\u662f\u5b58\u653e\u5728\u6808\u4e0a\u7684\uff0c\u800c\u6808\u4e0a\u662f\u4e0d\u5141\u8bb8\u5b58\u5728\u4e00\u4e2a\u5927\u5c0f\u4e0d\u53ef\u77e5\u7684\u6570\u636e\u7684\uff0c\u56e0\u6b64\u5982\u679c\u6211\u4eec\u60f3\u521b\u5efa\u67d0\u4e2a\u7c7b\u578b\u7684\u53d8\u91cf\uff0c\u90a3\u4e48\u8fd9\u4e2a\u7c7b\u578b\u5fc5\u987b\u6ee1\u8db3 Sized<\/code> \u7ea6\u675f\uff0c\u5373\u5b9a\u957f\u7c7b\u578b\u3002\u800c\u5bf9\u4e8e\u8fd9\u4e9b Unsized \u7c7b\u578b\uff0c\u6211\u4eec\u4f7f\u7528\u7684\u65f6\u5019\u5c31\u5fc5\u987b\u5305\u88f9\u4e00\u4e2a Sized<\/code> \u7684\u95f4\u63a5\u5c42\uff0c\u6bd4\u5982\u5f15\u7528 &<\/code> \u6216\u8005 Box<\/code>\u3002<\/p>\n

\u62ff\u6211\u4eec\u5e38\u89c1\u7684 &str<\/code> \u3001&[u8]<\/code> \u6765\u4e3e\u4f8b\uff1a<\/p>\n

    \n
  • \n

    &str<\/code> \u662f\u5bf9\u5b57\u7b26\u4e32\u5207\u7247\u7684\u5f15\u7528\uff0c\u5176\u5360\u7528\u7684\u5185\u5b58\u7a7a\u95f4\u662f\u56fa\u5b9a\u7684\uff0c\u5305\u542b\u4e24\u4e2a\u6210\u5458\uff1a\u4e00\u4e2a\u662f\u6307\u9488\uff0c\u6307\u5411\u8fde\u7eed\u7684 u8 \u6570\u636e\uff08\u5b58\u653e\u7740 UTF-8 \u5b57\u7b26\uff09\uff0c\u53e6\u4e00\u4e2a\u662f usize<\/code> \u7c7b\u578b\uff0c\u8868\u793a\u5b57\u8282\u7684\u6570\u91cf\u3002<\/p>\n<\/li>\n

  • \n

    \u5176\u5b83\u5207\u7247\u5f15\u7528\uff0c\u4f8b\u5982 &[T]<\/code>\uff0c\u5360\u7528\u7684\u5185\u5b58\u7a7a\u95f4\u4e5f\u662f\u56fa\u5b9a\u7684\uff0c\u540c\u6837\u5305\u542b\u4e24\u4e2a\u6210\u5458\uff1a\u4e00\u4e2a\u6307\u5411\u8fde\u7eed\u6570\u636e\u7684\u6307\u9488\uff0c\u548c\u4e00\u4e2a\u8868\u793a\u5143\u7d20\u6570\u91cf\u7684\u8ba1\u6570\u3002<\/p>\n<\/li>\n<\/ul>\n

    \n

    \u540c\u7406\uff0c\u7279\u5f81\u5bf9\u8c61 dyn Trait<\/code> \u672c\u8eab\u4e5f\u662f\u4e0d\u5b9a\u957f\u7c7b\u578b\uff0c\u4e5f\u8981\u52a0\u4e0a\u5f15\u7528\u6216\u8005 Box<\/code> \u624d\u80fd\u64cd\u4f5c\u3002<\/p>\n

    \u8bfb\u5230\u8fd9\u91cc\uff0c\u4f60\u53ef\u80fd\u4f1a\u6709\u7591\u60d1\uff1a\u7edd\u5927\u591a\u6570\u5207\u7247\u90fd\u662f []<\/code> \u5305\u8d77\u6765\u7684\u5f62\u5f0f\uff0c\u4f46\u4e3a\u4ec0\u4e48\u8981\u4e3a\u5b57\u7b26\u4e32\u5207\u7247\u5355\u72ec\u8bbe\u8ba1\u4e2a str<\/code> \u5462\uff1f[char]<\/code> \u53c8\u662f\u4ec0\u4e48\uff1f\u5148\u4e0d\u6025\uff0c\u6211\u4eec\u540e\u9762\u4f1a\u8bb2\u3002<\/p>\n<\/blockquote>\n

    \u4ece\u4ee3\u7801\u89d2\u5ea6\u6765\u770b\uff0c&str<\/code> \u53ef\u80fd\u957f\u8fd9\u6837\uff08\u6ce8\uff0c\u53ea\u662f\u8bf4\u660e\uff0c\u53ef\u80fd\u5e76\u975e\u771f\u5b9e\u4ee3\u7801\uff09\uff1a<\/p>\n

    struct &str {\n    data: *const u8,\n    len: usize,\n}<\/code><\/pre>\n
    1.2. String<\/code><\/h3>\n
    String<\/code> \u662f\u4e00\u4e2a\u53ef\u53d8\u7684\u3001\u5806\u4e0a\u5206\u914d\u7684 UTF-8 \u7684 u8 \u7f13\u51b2\u533a\u3002\u8fd9\u610f\u5473\u7740 String<\/code> \u62e5\u6709\u4e00\u5757\u5806\u4e0a\u5206\u914d\u7684\u5185\u5b58\u7684\u6240\u6709\u6743\uff0c\u5b83\u7528\u8fd9\u5757\u7a7a\u95f4\u5b58\u653e\u6570\u636e\uff0c\u5e76\u53ef\u4ee5\u8c03\u6574\u5927\u5c0f\u3002<\/p>\n
    \u5728\u6807\u51c6\u5e93\u4e2d\u6211\u4eec\u53ef\u4ee5\u770b\u5230 String<\/code> \u7684\u539f\u578b\uff1a<\/p>\n
    pub struct String {\n    vec: Vec<u8>,\n}<\/code><\/pre>\n
    1.3. &str<\/code> \u4e0e String<\/code> \u7684\u533a\u522b<\/h3>\n
    \u5728\u524d\u9762\u4e24\u4e2a\u5c0f\u8282\u4e2d\uff0c\u6211\u4eec\u5206\u522b\u5bf9\u8fd9\u4e09\u79cd\u7c7b\u578b\u505a\u51fa\u4e86\u5b9a\u4e49\uff1astr<\/code> \u672c\u8d28\u662f\u5b57\u7b26\u4e32\u5207\u7247\uff0c&str<\/code> \u662f\u5b57\u7b26\u4e32\u5207\u7247\u7684\u5f15\u7528\uff0cString<\/code> \u662f\u5bf9\u6570\u636e\u62e5\u6709\u6240\u6709\u6743\u7684\u5806\u4e0a\u5b57\u8282\u7f13\u51b2\u533a\u3002\u4ece\u8fd9\u4e9b\u5b9a\u4e49\u51fa\u53d1\uff0c\u6211\u4eec\u53ef\u4ee5\u53d1\u73b0 &str<\/code> \u4e0e String<\/code> \u6709\u5982\u4e0b\u51e0\u9879\u91cd\u8981\u7684\u533a\u522b\uff1a<\/p>\n
      \n
    • \n
      \u6240\u6709\u6743<\/strong>\uff1aString<\/code> \u62e5\u6709\u6570\u636e\u7684\u6240\u6709\u6743\uff1b\u800c &str<\/code> \u53ea\u662f\u5207\u7247\uff0c\u5e76\u4e0d\u62e5\u6709\u6240\u6709\u6743<\/p>\n<\/li>\n
    • \n
      \u7a7a\u95f4\u62d3\u5c55\u6027<\/strong>\uff1a\u663e\u7136\uff0c\u5207\u7247\u4f5c\u4e3a\uff08\u90e8\u5206\uff09\u5f15\u7528\uff0c\u4e0d\u80fd\u6269\u5c55\u5176\u6307\u5411\u7684\u6570\u636e\u7a7a\u95f4\uff1b\u800c String<\/code> \u7528\u6709\u8fd9\u5757\u5806\u4e0a\u6570\u636e\u7684\u6240\u6709\u6743\uff0c\u56e0\u6b64\u5728\u9700\u8981\u7684\u65f6\u5019\u53ef\u4ee5\u8fdb\u884c\u6269\u5bb9\u3002<\/p>\n<\/li>\n
    • \n
      \u5e95\u5c42\u6570\u636e\u5b58\u653e\u4f4d\u7f6e<\/strong>\uff1aString<\/code> \u7684\u5b57\u7b26\u4e32\u6570\u636e\u4e00\u5b9a\u5b58\u653e\u5728\u5806\u4e0a\uff1b\u800c &str<\/code> \u7531\u4e8e\u662f\u5207\u7247\uff0c\u53ea\u662f\u4e00\u4e2a\u5f15\u7528\uff0c\u5176\u6570\u636e\u5b58\u653e\u7684\u4f4d\u7f6e\u8981\u89c6\u501f\u7528\u5bf9\u8c61\u800c\u5b9a\u3002\u53ef\u4ee5\u5206\u6210\u5982\u4e0b\u51e0\u79cd\u60c5\u51b5\uff1a<\/p>\n
        \n
      • \u5f15\u7528\u7684\u5bf9\u8c61\u662f\u5b57\u9762\u91cf\uff08String literal\uff09\uff0c\u5219\u6570\u636e\u5b58\u653e\u5728 .data \u6bb5\u4e2d\uff1b<\/li>\n
      • \u5f15\u7528\u7684\u5bf9\u8c61\u662f\u6570\u7ec4\uff0c\u5219\u6570\u636e\u5b58\u653e\u5728\u6808\u4e0a\uff1b<\/li>\n
      • \u5f15\u7528\u7684\u5bf9\u8c61\u662f String<\/code> \uff0c\u5219\u6570\u636e\u5b58\u653e\u5728\u5806\u4e0a\u3002<\/li>\n
      • \u7279\u522b\u5730\uff0c\u5982\u679c\u6570\u7ec4\u8fc7\u4e8e\u5de8\u5927\uff0c\u653e\u5728\u6808\u4e0a\u4f1a\u5bfc\u81f4\u7206\u6808\uff0c\u6b64\u65f6 rust \u7f16\u8bd1\u5668\u4f1a\u8f6c\u800c\u5c06\u5176\u5b58\u653e\u5230\u5806\u4e0a\uff0c&str<\/code> \u7684\u6570\u636e\u5b58\u653e\u4f4d\u7f6e\u4e5f\u5728\u5806\u4e0a\u4e86\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
        1.4. \u53e6\u4e00\u4e2a\u533a\u522b\uff1a\u53ef\u4fee\u6539\u6027<\/h3>\n
        \u7531\u4e8e String<\/code> \u62e5\u6709\u6570\u636e\u7684\u6240\u6709\u6743\uff0c\u56e0\u6b64\u53ea\u8981 String<\/code> \u53d8\u91cf\u662f mut<\/code> \u7684\uff0c\u5c31\u53ef\u4ee5\u968f\u610f\u5bf9\u6570\u636e\u8fdb\u884c\u589e\u5220\u6539\uff0c\u4f8b\u5982\uff1a<\/p>\n
        let mut s = String::from("Hello ");\ns.push_str("rust");<\/code><\/pre>\n
        \u4f46\u662f\uff0c\u5b57\u7b26\u4e32\u5207\u7247\uff0c\u5373\u4f7f\u88ab\u5b9a\u4e49\u6210 &mut str<\/code> \u7684\u5f62\u5f0f\uff0c\u4e5f\u53ea\u80fd\u7ecf\u7531 unsafe \u7684\u65b9\u6cd5\u6765\u4fee\u6539\u6570\u636e\u3002\u6362\u8a00\u4e4b\uff0c\u5728 safe rust \u4e2d\uff0c&str<\/code> \u662f\u65e0\u8bba\u5982\u4f55\u90fd\u4e0d\u80fd\u4fee\u6539\u6570\u636e\u7684\u3002\u8fd9\u4e00\u70b9\u4e0e\u5176\u4ed6\u7c7b\u578b\u7684\u5207\u7247\u5927\u76f8\u5f84\u5ead\u3002<\/p>\n
        \/\/ u8 \u7c7b\u578b\u5207\u7247\uff0c\u53ef\u4ee5\u4fee\u6539\u5f15\u7528\u7684\u6570\u636e\nlet mut arr: [u8; 5] = [1, 2, 3, 4, 5];\nlet reference = &mut arr[1..2];\nreference[0] = 1;\nprintln!("{arr:?}"); \/\/ \u6253\u5370\uff1a[1, 1, 3, 4, 5]\n\n\/\/ \u5b57\u7b26\u4e32\u5207\u7247\uff0c\u53ea\u80fd\u901a\u8fc7 unsafe \u65b9\u6cd5\u8f6c\u4e3a &mut [u8] \u6765\u4fee\u6539\nlet mut my_string = String::from("Hello, world!");\nlet my_str_slice: &mut str = &mut my_string[..];\nlet bytes: &mut [u8] = unsafe { my_str_slice.as_bytes_mut() };\nbytes[7..12].copy_from_slice(b"Rust!");\nprintln!("{}", my_string); \/\/ \u6253\u5370\uff1aHello, Rust!!<\/code><\/pre>\n
        \u56e0\u6b64\uff0c&str<\/code> \u5728 safe rust \u4e2d\u53ea\u80fd\u4f5c\u4e3a\u4e00\u79cd\u53ea\u8bfb\u5207\u7247\uff0c\u5c3d\u7ba1\u5176\u4ed6\u7684\u5207\u7247\u7c7b\u578b\u90fd\u53ef\u4ee5\u88ab\u5b9a\u4e49\u6210\u53ef\u5199\u7684\u3002<\/p>\n
        1.5. &mut str<\/code> \u5728 safe rust \u4e2d\u4e0d\u80fd\u4fee\u6539\u6307\u5411\u6570\u636e\u7684\u539f\u56e0<\/h3>\n
        \u5b58\u5728\u8fd9\u4e2a\u9650\u5236\u7684\u4e3b\u8981\u539f\u56e0\u662f &str<\/code> \uff08\u8fd8\u6709 String<\/code>\uff09\u5f3a\u5236\u91c7\u7528 UTF-8 \u7f16\u7801\u3002UTF-8 \u7f16\u7801\u4e2d\uff0c\u4e00\u4e2a\u5b57\u7b26\u7684\u957f\u5ea6\u662f\u4e0d\u56fa\u5b9a\u7684\uff0c\u53ef\u80fd\u662f 1~4 \u5b57\u8282\uff0c\u89c6\u5176\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u524d\u51e0\u4f4d\u800c\u5b9a\uff1a<\/p>\n
          \n
        • \u7b2c\u4e00\u4e2a bit \u662f 0\uff0c\u5219\u662f\u4e00\u4e2a\u5355\u5b57\u8282\u5b57\u7b26\uff0c\u5373 ASCII<\/li>\n
        • \u524d\u4e09\u4e2a bit \u662f 110\uff0c\u5219\u662f\u4e2a\u4e8c\u5b57\u8282\u5b57\u7b26<\/li>\n
        • \u524d\u56db\u4e2a bit \u662f 1110\uff0c\u5219\u662f\u4e2a\u4e09\u5b57\u8282\u5b57\u7b26<\/li>\n
        • \u524d\u4e94\u4e2a bit \u662f 11110\uff0c\u5219\u662f\u4e2a\u56db\u5b57\u8282\u5b57\u7b26<\/li>\n<\/ul>\n
          \u5982\u679c\u6211\u4eec\u60f3\u901a\u8fc7 &mut str<\/code> \u4fee\u6539\u6307\u5411\u7684\u6570\u636e\uff0c\u90a3\u4e48\u53ef\u80fd\u4f1a\u51fa\u73b0\u9700\u8981\u4fee\u6539\u6570\u636e\u957f\u5ea6\u7684\u60c5\u51b5\uff0c\u4f8b\u5982\u628a\u67d0\u4e2a\u5355\u5b57\u8282\u5b57\u7b26\u6539\u6210\u4e86\u591a\u5b57\u8282\u5b57\u7b26\u3002\u7136\u800c\uff0c\u5207\u7247\u4f5c\u4e3a\u4e00\u79cd\u5f15\u7528\uff0c\u5e76\u4e0d\u5177\u6709\u6570\u636e\u7684\u6240\u6709\u6743\uff0c\u56e0\u800c\u65e0\u6743\u5bf9\u6570\u636e\u7684\u957f\u5ea6\u8fdb\u884c\u53d8\u52a8\u3002\u6240\u4ee5\uff0c\u8fd9\u79cd\u64cd\u4f5c\u5728 safe rust \u4e2d\u662f\u4e0d\u53ef\u884c\u7684\u3002rust \u8bbe\u8ba1\u8005\u4eec\u7684\u60f3\u6cd5\u662f\uff0c\u63d0\u4f9b\u4e00\u4e2a unsafe \u65b9\u6cd5\uff0c\u8ba9\u8c03\u7528\u8005\u81ea\u5df1\u4fdd\u8bc1\u4fee\u6539\u540e\u7684\u7ed3\u679c\u4f9d\u7136\u662f\u6b63\u786e\u7684 UTF-8 \u7f16\u7801\u3002<\/p>\n
          2. char<\/h2>\n
          char<\/code> \u662f rust \u4e2d\u7684\u53e6\u4e00\u79cd\u5b57\u7b26\u7c7b\u578b\u3002\u524d\u9762\u6211\u4eec\u63d0\u5230\uff0c &str<\/code> \u548c String<\/code> \u90fd\u8981\u6c42\u662f UTF-8 \u7f16\u7801\uff0c\u4f46 char<\/code> \u662f unicode \u7f16\u7801\uff0c\u5176\u6bcf\u4e2a\u5b57\u7b26\u957f\u5ea6\u662f\u56fa\u5b9a\u7684 4 \u5b57\u8282\u3002<\/p>\n
          \u6b64\u5916\uff0cchar<\/code> \u672c\u8eab\u5c31\u662f\u4e00\u79cd\u57fa\u672c\u7c7b\u578b\uff0c\u800c &str<\/code> \u548c String<\/code> \u672c\u8d28\u4e0a\u90fd\u662f\u57fa\u4e8e\u53e6\u4e00\u79cd\u57fa\u672c\u7c7b\u578b\u2014\u2014 u8<\/code> \u7684\u3002<\/p>\n
          \u7531\u4e8e\u4ee5\u4e0a\u8fd9\u4e24\u70b9\uff0cchar<\/code> \u4e0e &str<\/code> String<\/code> \u4e4b\u95f4\u5b58\u5728\u7740\u663e\u8457\u7684\u533a\u522b\u3002\u5f53\u7136\uff0c\u6211\u4eec\u4e5f\u80fd\u6bd4\u8f83\u65b9\u4fbf\u5730\u5728\u4e8c\u8005\u4e4b\u95f4\u8f6c\u6362\u3002<\/p>\n
          \u5230\u5e95\u4f7f\u7528\u54ea\u4e00\u65b9\uff0c\u4e3b\u8981\u8fd8\u662f\u89c6\u6211\u4eec\u4e1a\u52a1\u573a\u666f\u4e2d\u9700\u8981\u4f7f\u7528\u5230\u7684\u7f16\u7801\u7c7b\u578b\u6765\u8003\u8651\u3002\u5982\u679c\u9700\u8981 unicode \u7f16\u7801\uff0c\u5219\u6211\u4eec\u9700\u8981\u4f7f\u7528 Vec<char><\/code> \u548c &[char]<\/code> \uff1b\u5982\u679c UTF-8 \u53ef\u4ee5\u6ee1\u8db3\u9700\u6c42\uff0c\u90a3\u4e48\u5c31\u53ef\u4ee5\u4f7f\u7528 String<\/code> \u548c &str<\/code> \uff0c\u4ece\u800c\u8282\u7701\u5185\u5b58\u7a7a\u95f4\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
          1. String, &str \u548c str \u60f3\u8981\u641e\u6e05\u695a\u8fd9\u4e09\u8005\u7684\u5dee\u522b\uff0c\u8981\u4ece str \u5f00\u59cb\u8bf4\u8d77\u3002 1.1. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[24],"class_list":["post-353","post","type-post","status-publish","format-standard","hentry","category-rust","tag-rust"],"_links":{"self":[{"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/posts\/353","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/comments?post=353"}],"version-history":[{"count":0,"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/posts\/353\/revisions"}],"wp:attachment":[{"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/media?parent=353"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/categories?post=353"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cococat.top\/index.php\/wp-json\/wp\/v2\/tags?post=353"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}