{"id":7431,"date":"2026-07-22T12:16:15","date_gmt":"2026-07-22T04:16:15","guid":{"rendered":"https:\/\/i007.cc\/wordpress\/?p=7431"},"modified":"2026-07-22T12:17:06","modified_gmt":"2026-07-22T04:17:06","slug":"lambda-%e5%ba%95%e5%b1%82%e5%88%b0%e5%ba%95%e6%98%af%e6%80%8e%e4%b9%88%e5%ae%9e%e7%8e%b0%e7%9a%84%ef%bc%88%e7%bc%96%e8%af%91%e5%99%a8%e5%85%b6%e5%ae%9e%e6%8a%8a%e5%ae%83%e8%bd%ac%e6%8d%a2%e6%88%90","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/7431","title":{"rendered":"Lambda \u5e95\u5c42\u5230\u5e95\u662f\u600e\u4e48\u5b9e\u73b0\u7684\uff08\u7f16\u8bd1\u5668\u5176\u5b9e\u628a\u5b83\u8f6c\u6362\u6210\u4e86\u4e00\u4e2a\u4eff\u51fd\u6570\u7c7b\uff09"},"content":{"rendered":"

\ud83d\udd37 \u6838\u5fc3\u771f\u76f8\uff1aLambda \u4e0d\u662f”\u9b54\u6cd5”\uff0c\u662f\u8bed\u6cd5\u7cd6<\/h3>\n

\u5f53\u4f60\u5199\uff1a<\/p>\n

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cpp<\/div>\n
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int threshold = 5;\r\nauto isAbove = [threshold](int x) { return x > threshold; };<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u7f16\u8bd1\u5668\u5728\u80cc\u540e\u6084\u6084\u628a\u5b83\u7ffb\u8bd1<\/strong>\u6210\u4e86\u4e00\u4e2a\u7c7b\uff08\u4e13\u4e1a\u672f\u8bed\u53eb\u4eff\u51fd\u6570 \/ functor<\/strong>\uff09\uff1a<\/p>\n
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cpp<\/div>\n
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\/\/ \u7f16\u8bd1\u5668\u751f\u6210\u7684\"\u5e55\u540e\u771f\u76f8\"\uff0c\u5927\u81f4\u957f\u8fd9\u6837\uff1a\r\nclass __Lambda_xyz {\r\nprivate:\r\n    int threshold;   \/\/ \u6355\u83b7\u7684\u53d8\u91cf\uff0c\u53d8\u6210\u4e86\u7c7b\u7684\u6210\u5458\u53d8\u91cf\uff01\r\n\r\npublic:\r\n    \/\/ \u6784\u9020\u51fd\u6570\uff1a\u5b9a\u4e49 Lambda \u65f6\uff0c\u628a\u5916\u90e8\u53d8\u91cf\u62f7\u8d1d\u8fdb\u6210\u5458\u53d8\u91cf\r\n    __Lambda_xyz(int t) : threshold(t) {}\r\n\r\n    \/\/ operator() \uff1a\u8ba9\u5bf9\u8c61\u53ef\u4ee5\u50cf\u51fd\u6570\u4e00\u6837\u88ab\u8c03\u7528\r\n    bool operator()(int x) const {\r\n        return x > threshold;\r\n    }\r\n};\r\n\r\n\/\/ auto isAbove = [threshold](int x) {...}; \r\n\/\/ \u5b9e\u9645\u4e0a\u7b49\u4ef7\u4e8e\uff1a\r\n__Lambda_xyz isAbove(threshold);  \/\/ \u521b\u5efa\u5bf9\u8c61\uff0c\u6784\u9020\u51fd\u6570\u91cc\u62f7\u8d1d\u4e86 threshold<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u8c03\u7528 isAbove(10)<\/code> \u65f6\uff0c\u5b9e\u9645\u6267\u884c\u7684\u662f isAbove.operator()(10)<\/code>\u3002<\/p>\n
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\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48 Lambda \u80fd”\u6355\u83b7”\u2014\u2014\u6355\u83b7\u7684\u53d8\u91cf\u6839\u672c\u4e0d\u662f\u4ec0\u4e48\u7279\u6b8a\u673a\u5236\uff0c\u5c31\u662f\u666e\u901a\u7684\u7c7b\u6210\u5458\u53d8\u91cf\uff0c\u5728\u6784\u9020\u51fd\u6570\u91cc\u88ab\u62f7\u8d1d\u8fdb\u53bb\u800c\u5df2\uff01<\/strong><\/p>\n<\/blockquote>\n
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\ud83d\udd37 \u503c\u6355\u83b7 vs \u5f15\u7528\u6355\u83b7 \u2192 \u5bf9\u5e94\u4e0d\u540c\u7684\u6210\u5458\u53d8\u91cf\u7c7b\u578b<\/h3>\n
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cpp<\/div>\n
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int x = 10;\r\n\r\n\/\/ \u503c\u6355\u83b7 [x]\r\nauto byValue = [x]() { return x; };<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u7ffb\u8bd1\u4e3a\uff1a<\/p>\n
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cpp<\/div>\n
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class Lambda_ByValue {\r\n    int x;   \/\/ \u6210\u5458\u53d8\u91cf\u662f int\uff08\u62f7\u8d1d\u7684\u503c\uff09\r\npublic:\r\n    Lambda_ByValue(int x_) : x(x_) {}\r\n    int operator()() const { return x; }\r\n};<\/pre>\n
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cpp<\/div>\n
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\/\/ \u5f15\u7528\u6355\u83b7 [&x]\r\nauto byRef = [&x]() { return x; };<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u7ffb\u8bd1\u4e3a\uff1a<\/p>\n
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cpp<\/div>\n
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class Lambda_ByRef {\r\n    int& x;   \/\/ \u6210\u5458\u53d8\u91cf\u662f int&\uff08\u5f15\u7528\uff01\uff09\r\npublic:\r\n    Lambda_ByRef(int& x_) : x(x_) {}\r\n    int operator()() const { return x; }\r\n};<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
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\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u5f15\u7528\u6355\u83b7\u5728\u53d8\u91cf\u9500\u6bc1\u540e\u4f1a\u60ac\u7a7a<\/strong>\u2014\u2014\u672c\u8d28\u5c31\u662f\u4e00\u4e2a\u60ac\u7a7a\u5f15\u7528\u6210\u5458\u53d8\u91cf<\/strong>\uff0c\u548c\u4f60\u624b\u5199\u4e00\u4e2a\u6301\u6709\u5f15\u7528\u6210\u5458\u7684\u7c7b\u72af\u7684\u9519\u8bef\u4e00\u6a21\u4e00\u6837\u3002<\/p>\n<\/blockquote>\n
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\ud83d\udd37 \u4e3a\u4ec0\u4e48\u503c\u6355\u83b7\u9ed8\u8ba4 const<\/code>\uff0c\u52a0 mutable<\/code> \u624d\u80fd\u6539\uff1f<\/h3>\n
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cpp<\/div>\n
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auto lambda = [x]() { return x; };<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u7ffb\u8bd1\u4e3a\uff1a<\/p>\n
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cpp<\/div>\n
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class Lambda {\r\n    int x;\r\npublic:\r\n    Lambda(int x_) : x(x_) {}\r\n    int operator()() const {  \/\/ \u2190 \u6ce8\u610f\u8fd9\u4e2a const\uff01\r\n        return x;\r\n    }\r\n};<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
operator()<\/code> \u9ed8\u8ba4\u662f const<\/code> \u6210\u5458\u51fd\u6570<\/strong>\uff0c\u6240\u4ee5\u51fd\u6570\u4f53\u5185\u4e0d\u80fd\u4fee\u6539\u4efb\u4f55\u6210\u5458\u53d8\u91cf\uff08\u5305\u62ec x<\/code>\uff09\u3002<\/p>\n
\u52a0\u4e0a mutable<\/code> \u4e4b\u540e\uff1a<\/p>\n
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cpp<\/div>\n
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auto lambda = [x]() mutable { x++; return x; };<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u7ffb\u8bd1\u4e3a\uff1a<\/p>\n
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cpp<\/div>\n
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class Lambda {\r\n    int x;\r\npublic:\r\n    Lambda(int x_) : x(x_) {}\r\n    int operator()() {   \/\/ \u2190 mutable \u53bb\u6389\u4e86 const\uff01\r\n        x++;\r\n        return x;\r\n    }\r\n};<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
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mutable<\/code> \u5173\u952e\u5b57\u672c\u8d28\u4e0a\u5c31\u662f\u628a operator()<\/code> \u4ece const<\/code> \u51fd\u6570\u53d8\u6210\u666e\u901a\u51fd\u6570\u3002<\/strong><\/p>\n<\/blockquote>\n
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\ud83d\udd37 \u9a8c\u8bc1\uff1a\u7528 typeid<\/code> \u770b\u770b Lambda \u7684\u771f\u5b9e\u7c7b\u578b<\/h3>\n
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cpp<\/div>\n
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#include <iostream>\r\n#include <typeinfo>\r\n\r\nint main() {\r\n    auto lambda = [](int x) { return x * 2; };\r\n    \r\n    std::cout << typeid(lambda).name() << std::endl;\r\n    \/\/ \u8f93\u51fa\u7c7b\u4f3c\uff1aZ4mainEUliE_ \uff08\u7f16\u8bd1\u5668\u751f\u6210\u7684\u4e71\u7801\u7c7b\u540d\uff09\r\n    \/\/ \u4e0d\u662f \"function\" \u6216\u4efb\u4f55\u5185\u7f6e\u7c7b\u578b \u2014\u2014 \u8bc1\u660e\u5b83\u662f\u4e00\u4e2a\u72ec\u7acb\u7684\u7c7b\uff01\r\n}<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u6bcf\u4e2a Lambda \u8868\u8fbe\u5f0f\uff0c\u54ea\u6015\u4ee3\u7801\u957f\u5f97\u4e00\u6a21\u4e00\u6837\uff0c\u90fd\u4f1a\u751f\u6210\u4e00\u4e2a\u72ec\u4e00\u65e0\u4e8c\u7684\u533f\u540d\u7c7b<\/strong>\uff1a<\/p>\n
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cpp<\/div>\n
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auto l1 = [](int x) { return x + 1; };\r\nauto l2 = [](int x) { return x + 1; };\r\n\r\n\/\/ l1 \u548c l2 \u662f\u4e0d\u540c\u7684\u7c7b\u578b\uff01\u5373\u4f7f\u903b\u8f91\u5b8c\u5168\u76f8\u540c\r\n\/\/ decltype(l1) \u548c decltype(l2) \u662f\u4e24\u4e2a\u4e0d\u540c\u7684\u533f\u540d\u7c7b<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
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\ud83d\udd37 \u4e3a\u4ec0\u4e48 Lambda \u80fd\u76f4\u63a5\u4f20\u7ed9 STL \u7b97\u6cd5\uff08\u6027\u80fd\u4f18\u52bf\uff09<\/h3>\n
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cpp<\/div>\n
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std::sort(v.begin(), v.end(), \r\n    [](int a, int b) { return a > b; });<\/pre>\n
 <\/p>\n<\/div>\n<\/div>\n
\u56e0\u4e3a Lambda \u662f\u5177\u4f53\u7c7b\u578b<\/strong>\uff08\u4e0d\u662f\u51fd\u6570\u6307\u9488\uff09\uff0c\u7f16\u8bd1\u5668\u5728\u7f16\u8bd1\u671f\u5c31\u77e5\u9053 operator()<\/code> \u7684\u5177\u4f53\u5b9e\u73b0\uff0c\u53ef\u4ee5\u76f4\u63a5\u5185\u8054\u5c55\u5f00<\/strong>\uff0c\u6ca1\u6709\u51fd\u6570\u6307\u9488\u8c03\u7528\u7684\u95f4\u63a5\u8df3\u8f6c\u5f00\u9500\u3002<\/p>\n
\u5bf9\u6bd4\uff1a<\/p>\n
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cpp<\/div>\n
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\/\/ \u51fd\u6570\u6307\u9488\u7248\u672c\uff1a\u8fd0\u884c\u65f6\u901a\u8fc7\u6307\u9488\u8df3\u8f6c\u8c03\u7528\uff0c\u96be\u4ee5\u5185\u8054\r\nbool cmp(int a, int b) { return a > b; }\r\nstd::sort(v.begin(), v.end(), cmp);  \/\/ \u6027\u80fd\u7565\u900a\u4e8e Lambda\r\n\r\n\/\/ Lambda \u7248\u672c\uff1a\u7f16\u8bd1\u5668\u77e5\u9053\u786e\u5207\u7c7b\u578b\uff0c\u51e0\u4e4e\u603b\u80fd\u5185\u8054\uff0c\u96f6\u5f00\u9500\r\nstd::sort(v.begin(), v.end(), [](int a, int b) { return a > b; });<\/pre>\n
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\u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48\u73b0\u4ee3 C++ \u63d0\u5021”\u4f18\u5148\u7528 Lambda \u800c\u4e0d\u662f\u51fd\u6570\u6307\u9488”\u2014\u2014Lambda \u6027\u80fd\u66f4\u597d\uff0c\u4e0d\u662f\u56e0\u4e3a\u8bed\u6cd5\u65b0\u6f6e\uff0c\u800c\u662f\u7c7b\u578b\u7cfb\u7edf\u7ed9\u4e86\u7f16\u8bd1\u5668\u66f4\u591a\u4f18\u5316\u4fe1\u606f<\/strong>\u3002<\/p>\n<\/blockquote>\n
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\ud83d\udd37 \u5b8c\u6574\u5bf9\u7167\u8868<\/h3>\n
\n\n\n\n\n\n\n\n\n\n\n
Lambda \u5199\u6cd5<\/th>\n\u7f16\u8bd1\u5668\u751f\u6210\u7684\u7b49\u4ef7\u4ee3\u7801<\/th>\n<\/tr>\n<\/thead>\n
[x](){...}<\/code><\/td>\n\u6210\u5458\u53d8\u91cf int x<\/code>\uff0c\u6784\u9020\u51fd\u6570\u62f7\u8d1d\u8d4b\u503c<\/td>\n<\/tr>\n
[&x](){...}<\/code><\/td>\n\u6210\u5458\u53d8\u91cf int& x<\/code>\uff0c\u6784\u9020\u51fd\u6570\u5f15\u7528\u7ed1\u5b9a<\/td>\n<\/tr>\n
[](){...}<\/code> (\u65e0\u6355\u83b7)<\/td>\n\u65e0\u6210\u5458\u53d8\u91cf\u7684\u7a7a\u7c7b\uff08\u53ef\u9690\u5f0f\u8f6c\u51fd\u6570\u6307\u9488\uff09<\/td>\n<\/tr>\n
[x]() mutable {...}<\/code><\/td>\noperator()<\/code> \u53bb\u6389 const<\/code><\/td>\n<\/tr>\n
[=](){...}<\/code><\/td>\n\u628a\u7528\u5230\u7684\u5916\u90e8\u53d8\u91cf\u9010\u4e2a\u503c\u6355\u83b7\uff0c\u751f\u6210\u5bf9\u5e94\u6210\u5458<\/td>\n<\/tr>\n
[&](){...}<\/code><\/td>\n\u628a\u7528\u5230\u7684\u5916\u90e8\u53d8\u91cf\u9010\u4e2a\u5f15\u7528\u6355\u83b7\uff0c\u751f\u6210\u5bf9\u5e94\u6210\u5458<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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\u4e00\u53e5\u8bdd\u603b\u7ed3<\/h3>\n
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Lambda = \u7f16\u8bd1\u5668\u81ea\u52a8\u751f\u6210\u7684\u4e00\u4e2a”\u4eff\u51fd\u6570\u7c7b” + \u81ea\u52a8\u5e2e\u4f60\u5199\u597d\u6784\u9020\u51fd\u6570\u548c operator()<\/code>\u3002<\/strong> \u6355\u83b7\u5217\u8868\u672c\u8d28\u662f”\u58f0\u660e\u8fd9\u4e2a\u7c7b\u9700\u8981\u54ea\u4e9b\u6210\u5458\u53d8\u91cf”\uff0c\u51fd\u6570\u4f53\u672c\u8d28\u662f operator()<\/code> \u7684\u5b9e\u73b0\u3002\u7406\u89e3\u4e86\u8fd9\u70b9\uff0cLambda \u7684\u4e00\u5207\u884c\u4e3a\uff08\u6355\u83b7\u3001mutable\u3001\u751f\u547d\u5468\u671f\u9677\u9631\uff09\u90fd\u53d8\u5f97\u81ea\u7136\u800c\u7136\u3002<\/p>\n<\/blockquote>\n
\u60f3\u770b\u4e00\u4e0b\u65e0\u6355\u83b7\u7684 Lambda \u5982\u4f55\u9690\u5f0f\u8f6c\u6362\u6210\u51fd\u6570\u6307\u9488<\/strong>\u7684\u5e95\u5c42\u7ec6\u8282\u5417\uff1f\u8fd9\u4e5f\u662f\u4e00\u4e2a\u5f88\u591a\u4eba\u4f1a\u9047\u5230\u7684”\u4e3a\u4ec0\u4e48\u8fd9\u6837\u80fd\u7f16\u8bd1\u8fc7”\u7684\u7591\u95ee\u70b9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\ud83d\udd37 \u6838\u5fc3\u771f\u76f8\uff1aLambda \u4e0d\u662f&#82<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[24],"tags":[],"class_list":["post-7431","post","type-post","status-publish","format-standard","hentry","category-value_docs"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7431","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=7431"}],"version-history":[{"count":2,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7431\/revisions"}],"predecessor-version":[{"id":7433,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/7431\/revisions\/7433"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=7431"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=7431"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=7431"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}