{"id":45631,"date":"2023-11-24T00:24:07","date_gmt":"2023-06-05T15:39:20","guid":{"rendered":"https:\/\/www.silicloud.com\/zh\/blog\/45631-2\/"},"modified":"2024-05-04T10:29:51","modified_gmt":"2024-05-04T02:29:51","slug":"45631-2","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/zh\/blog\/45631-2\/","title":{"rendered":""},"content":{"rendered":"

\u306f\u3058\u3081\u306b<\/h2>\n

\u3053\u306e\u8a18\u4e8b\u306f rustc 1.4.0 (8ab8581f6 2015-10-27) \u3067\u52d5\u4f5c\u78ba\u8a8d\u3092\u3057\u3066\u3044\u307e\u3059\u3002<\/p>\n

Rust \u3067 sum<\/h2>\n

Rust\u3067\u306f\u73fe\u5728sum(\u96c6\u8a08)\u3092\u3059\u308b\u306b\u306f\u3001<\/p>\n

std::iter::Iterator – sum<\/p>\n

fn<\/span> sum<\/span><<\/span>S<\/span> =<\/span> Self<\/span>::<\/span>Item<\/span>><\/span>(<\/span>self<\/span>)<\/span> -><\/span> S<\/span> \r\nwhere<\/span> S<\/span>:<\/span> Add<\/span><<\/span>Self<\/span>::<\/span>Item<\/span>,<\/span> Output<\/span>=<\/span>S<\/span>><\/span> +<\/span> Zero<\/span>\r\n<\/code><\/pre>\n
\u3068\u3044\u3046\u30e1\u30bd\u30c3\u30c9\u304c\u7528\u610f\u3055\u308c\u3066\u3044\u308b\u306e\u3067\u3059\u304c\u3001\u73fe\u5728\u3053\u3061\u3089\u306funstable\u3068\u306a\u3063\u3066\u3044\u308b\u30e1\u30bd\u30c3\u30c9\u3067issue\u304c\u4e0a\u304c\u3063\u3066\u304a\u308a\u3001\u307e\u3060\u4f7f\u7528\u3092\u63a8\u5968\u3067\u304d\u307e\u305b\u3093\u3002
\n(rust v1.29.1\u73fe\u5728\u3067\u306f\u554f\u984c\u306a\u304f\u4f7f\u7528\u53ef\u80fd(std::iter::Iterator – sum))<\/p>\n
\u305d\u3053\u3067\u4ee3\u308f\u308a\u3068\u306a\u308b\u65b9\u6cd5\u306e\u7d39\u4ecb\u3067\u3059\u3002<\/p>\n
fold\u3092\u4f7f\u3046<\/h2>\n
let<\/span> sum<\/span>:<\/span> i64<\/span> =<\/span> array<\/span>.map<\/span>(|<\/span>a<\/span>|<\/span> a<\/span>.count<\/span> )<\/span>.fold<\/span>(<\/span>0<\/span>,<\/span> |<\/span>sum<\/span>,<\/span> i<\/span>|<\/span> sum<\/span> +<\/span> i<\/span>);<\/span>\r\n<\/code><\/pre>\n
\u3084\u3063\u3066\u3044\u308b\u3053\u3068\u306f\u305f\u3060\u306e\u52a0\u7b97\u3067\u3059\u304c\u3001for\u7b49\u3067\u56de\u3059\u3088\u308a\u3082\u3059\u3063\u304d\u308a\u3068\u304b\u3051\u307e\u3059\u3002<\/p>\n
\u8ffd\u8a18<\/h2>\n
\u30b3\u30e1\u30f3\u30c8\u6b04\u3088\u308a\u6559\u3048\u3066\u9802\u304d\u307e\u3057\u305f<\/p>\n
let<\/span> sum<\/span>:<\/span> i64<\/span> =<\/span> array<\/span>.iter<\/span>()<\/span>.fold<\/span>(<\/span>0<\/span>,<\/span> |<\/span>sum<\/span>,<\/span> a<\/span>|<\/span> sum<\/span> +<\/span> a<\/span>.count<\/span>);<\/span>\r\n<\/code><\/pre>\n
map\u306f\u7701\u7565\u3059\u308b\u3053\u3068\u304c\u53ef\u80fd\u3067\u3059\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u306f\u3058\u3081\u306b \u3053\u306e\u8a18\u4e8b\u306f rustc 1.4.0 (8ab8581f6 2015-10-27) \u3067\u52d5\u4f5c\u78ba\u8a8d\u3092\u3057\u3066\u3044 […]<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-45631","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"\n- Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/zh\/blog\/45631-2\/\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:description\" content=\"\u306f\u3058\u3081\u306b \u3053\u306e\u8a18\u4e8b\u306f rustc 1.4.0 (8ab8581f6 2015-10-27) \u3067\u52d5\u4f5c\u78ba\u8a8d\u3092\u3057\u3066\u3044 […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/zh\/blog\/45631-2\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - 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