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請教下javascript說如何利用indexOF()函數(shù)統(tǒng)計數(shù)組的？

JavaScript

呼啦一陣風 2023-02-11 17:13:09

利用indexOF()函數(shù)統(tǒng)計數(shù)組arr("a","b","d","d","c","d","d")中元素d中出現(xiàn)的次數(shù)，并同時返回其對應(yīng)的所有下標這道題

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不負相思意

TA貢獻1777條經(jīng)驗獲得超10個贊

function f(i, indexes){ var j = arr.indexOf('d', i); if(j == -1) return indexes; indexes.push(j); return f(++j, indexes);} var arr = ["a","b","d","d","c","d","d"];var indexes = f(0, []);console.log("'d' 出現(xiàn)了：" + indexes.length + "次，下標為：" + indexes);

反對回復 2023-02-15

一只甜甜圈

TA貢獻1836條經(jīng)驗獲得超5個贊

var results = []; var fromIndex = 0; var arr = ["a","b","d","d","c","d","d"]; while(fromIndex<arr.length){ index = arr.indexOf('d',fromIndex); if(index == -1){ break; } else{ results.push(index); fromIndex = index + 1; } }