{"id":755,"date":"2021-08-08T14:31:57","date_gmt":"2021-08-08T06:31:57","guid":{"rendered":"http:\/\/blog.xrhoujie.com\/?p=755"},"modified":"2021-08-09T15:41:40","modified_gmt":"2021-08-09T07:41:40","slug":"javascript%e4%b8%adfilter%e7%9a%84%e7%94%a8%e6%b3%95%e8%bd%ac","status":"publish","type":"post","link":"http:\/\/blog.xrhoujie.com\/?p=755","title":{"rendered":"javascript\u4e2dfilter\u7684\u7528\u6cd5(\u8f6c)"},"content":{"rendered":"<h1 class=\"postTitle\"><\/h1>\n<div class=\"postBody\">\n<div id=\"cnblogs_post_body\" class=\"blogpost-body blogpost-body-html\">\n<h4>filter<\/h4>\n<div class=\"x-wiki-content x-main-content\">\n<p>filter\u4e5f\u662f\u4e00\u4e2a\u5e38\u7528\u7684\u64cd\u4f5c\uff0c\u5b83\u7528\u4e8e\u628a<code>Array<\/code>\u7684\u67d0\u4e9b\u5143\u7d20\u8fc7\u6ee4\u6389\uff0c\u7136\u540e\u8fd4\u56de\u5269\u4e0b\u7684\u5143\u7d20\u3002<\/p>\n<p>\u548c<code>map()<\/code>\u7c7b\u4f3c\uff0c<code>Array<\/code>\u7684<code>filter()<\/code>\u4e5f\u63a5\u6536\u4e00\u4e2a\u51fd\u6570\u3002\u548c<code>map()<\/code>\u4e0d\u540c\u7684\u662f\uff0c<code>filter()<\/code>\u628a\u4f20\u5165\u7684\u51fd\u6570\u4f9d\u6b21\u4f5c\u7528\u4e8e\u6bcf\u4e2a\u5143\u7d20\uff0c\u7136\u540e\u6839\u636e\u8fd4\u56de\u503c\u662f<code>true<\/code>\u8fd8\u662f<code>false<\/code>\u51b3\u5b9a\u4fdd\u7559\u8fd8\u662f\u4e22\u5f03\u8be5\u5143\u7d20\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u5728\u4e00\u4e2a<code>Array<\/code>\u4e2d\uff0c\u5220\u6389\u5076\u6570\uff0c\u53ea\u4fdd\u7559\u5947\u6570\uff0c\u53ef\u4ee5\u8fd9\u4e48\u5199\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<pre>1 var arr = [1, 2, 4, 5, 6, 9, 10, 15];\r\n2 var r = arr.filter(function (x) {\r\n3     return x % 2 !== 0;\r\n4 });\r\n5 r; \/\/ [1, 5, 9, 15]<\/pre>\n<\/div>\n<p>\u628a\u4e00\u4e2a<code>Array<\/code>\u4e2d\u7684\u7a7a\u5b57\u7b26\u4e32\u5220\u6389\uff0c\u53ef\u4ee5\u8fd9\u4e48\u5199\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<pre>1 var arr = ['A', '', 'B', null, undefined, 'C', '  '];\r\n2 var r = arr.filter(function (s) {\r\n3     return s &amp;&amp; s.trim(); \/\/ \u6ce8\u610f\uff1aIE9\u4ee5\u4e0b\u7684\u7248\u672c\u6ca1\u6709trim()\u65b9\u6cd5\r\n4 });\r\n5 r; \/\/ ['A', 'B', 'C']<\/pre>\n<\/div>\n<p>\u53ef\u89c1\u7528<code>filter()<\/code>\u8fd9\u4e2a\u9ad8\u9636\u51fd\u6570\uff0c\u5173\u952e\u5728\u4e8e\u6b63\u786e\u5b9e\u73b0\u4e00\u4e2a\u201c\u7b5b\u9009\u201d\u51fd\u6570\u3002<\/p>\n<h3><a name=\"#-E5-9B-9E-E8-B0-83-E5-87-BD-E6-95-B0\"><\/a>\u56de\u8c03\u51fd\u6570<\/h3>\n<p><code>filter()<\/code>\u63a5\u6536\u7684\u56de\u8c03\u51fd\u6570\uff0c\u5176\u5b9e\u53ef\u4ee5\u6709\u591a\u4e2a\u53c2\u6570\u3002\u901a\u5e38\u6211\u4eec\u4ec5\u4f7f\u7528\u7b2c\u4e00\u4e2a\u53c2\u6570\uff0c\u8868\u793a<code>Array<\/code>\u7684\u67d0\u4e2a\u5143\u7d20\u3002\u56de\u8c03\u51fd\u6570\u8fd8\u53ef\u4ee5\u63a5\u6536\u53e6\u5916\u4e24\u4e2a\u53c2\u6570\uff0c\u8868\u793a\u5143\u7d20\u7684\u4f4d\u7f6e\u548c\u6570\u7ec4\u672c\u8eab\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<div class=\"cnblogs_code_toolbar\"><\/div>\n<pre>1 var arr = ['A', 'B', 'C'];\r\n2 var r = arr.filter(function (element, index, self) {\r\n3     console.log(element); \/\/ \u4f9d\u6b21\u6253\u5370'A', 'B', 'C'\r\n4     console.log(index); \/\/ \u4f9d\u6b21\u6253\u53700, 1, 2\r\n5     console.log(self); \/\/ self\u5c31\u662f\u53d8\u91cfarr\r\n6     return true;\r\n7 });<\/pre>\n<div class=\"cnblogs_code_toolbar\"><\/div>\n<\/div>\n<p>\u5229\u7528<code>filter<\/code>\uff0c\u53ef\u4ee5\u5de7\u5999\u5730\u53bb\u9664<code>Array<\/code>\u7684\u91cd\u590d\u5143\u7d20\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<div class=\"cnblogs_code_toolbar\"><\/div>\n<pre>1 'use strict';\r\n2 \r\n3 var\r\n4     r,\r\n5     arr = ['apple', 'strawberry', 'banana', 'pear', 'apple', 'orange', 'orange', 'strawberry'];\r\n6 r = arr.filter(function (element, index, self) {\r\n7     return self.indexOf(element) === index;\r\n8 });\r\n9 console.log(r.toString());<\/pre>\n<div class=\"cnblogs_code_toolbar\"><\/div>\n<\/div>\n<p>\u8fd0\u884c\u7ed3\u679c\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<pre>apple,strawberry,banana,pear,orange<\/pre>\n<\/div>\n<p>\u53bb\u9664\u91cd\u590d\u5143\u7d20\u4f9d\u9760\u7684\u662f<code>indexOf<\/code>\u603b\u662f\u8fd4\u56de\u7b2c\u4e00\u4e2a\u5143\u7d20\u7684\u4f4d\u7f6e\uff0c\u540e\u7eed\u7684\u91cd\u590d\u5143\u7d20\u4f4d\u7f6e\u4e0e<code>indexOf<\/code>\u8fd4\u56de\u7684\u4f4d\u7f6e\u4e0d\u76f8\u7b49\uff0c\u56e0\u6b64\u88ab<code>filter<\/code>\u6ee4\u6389\u4e86\u3002<\/p>\n<p>&nbsp;<\/p>\n<p>\u5c1d\u8bd5\u7528<code>filter()<\/code>\u7b5b\u9009\u51fa\u7d20\u6570\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<div class=\"cnblogs_code_toolbar\"><\/div>\n<pre> 1 'use strict';\r\n 2 \r\n 3 function get_primes(arr) {\r\n 4     var i;\r\n 5     return arr.filter(function (element) {  \r\n 6             var flag=true;  \r\n 7             if(element&lt;2){  \r\n 8             flag=false;  \r\n 9         }else {  \r\n10             for(var i=2;i&lt;element;i++){  \r\n11                 if (element%i==0){  \r\n12                     flag=false;  \r\n13                     break;  \r\n14                 }  \r\n15             }  \r\n16         }  \r\n17         return flag;  \r\n18     });\r\n19 }\r\n20 \r\n21 \/\/ \u6d4b\u8bd5:\r\n22 var\r\n23     x,\r\n24     r,\r\n25     arr = [];\r\n26 for (x = 1; x &lt; 100; x++) {\r\n27     arr.push(x);\r\n28 }\r\n29 r = get_primes(arr);\r\n30 if (r.toString() === [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97].toString()) {\r\n31     console.log('\u6d4b\u8bd5\u901a\u8fc7!');\r\n32 } else {\r\n33     console.log('\u6d4b\u8bd5\u5931\u8d25: ' + r.toString());\r\n34 }<\/pre>\n<div class=\"cnblogs_code_toolbar\"><\/div>\n<\/div>\n<p>\u8fd0\u884c\u7ed3\u679c\uff1a<\/p>\n<div class=\"cnblogs_code\">\n<pre>\u6d4b\u8bd5\u901a\u8fc7!<\/pre>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>filter filter\u4e5f\u662f\u4e00\u4e2a\u5e38\u7528\u7684\u64cd\u4f5c\uff0c\u5b83\u7528\u4e8e\u628aArray\u7684\u67d0\u4e9b\u5143\u7d20\u8fc7\u6ee4\u6389\uff0c\u7136\u540e\u8fd4\u56de\u5269\u4e0b\u7684\u5143\u7d20\u3002 \u548cma [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":180,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[10],"tags":[19],"_links":{"self":[{"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=\/wp\/v2\/posts\/755"}],"collection":[{"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=755"}],"version-history":[{"count":2,"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=\/wp\/v2\/posts\/755\/revisions"}],"predecessor-version":[{"id":773,"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=\/wp\/v2\/posts\/755\/revisions\/773"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=\/wp\/v2\/media\/180"}],"wp:attachment":[{"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=755"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=755"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blog.xrhoujie.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=755"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}