JavaScript数组操作：删除奇数数组元素

Question

我需要帮助，我有一个像这样的数组：

myarray = ["nonsense","goodpart","nonsense2","goodpar2t","nonsense3","goodpart3",]

我需要从数组中删除所有“无意义”的部分。

“无意义”总是具有偶数索引。

- Andrius Mozuraitis

Answer 1

基于问题中所述的“胡言乱语”单词总是“偶数”元素的情况，我建议：

var myarray = ["nonsense", "goodpart", "nonsense2", "goodpar2t", "nonsense3", "goodpart3"],
  filtered = myarray.filter(function(el, index) {
    // normally even numbers have the feature that number % 2 === 0;
    // JavaScript is, however, zero-based, so want those elements with a modulo of 1:
    return index % 2 === 1;
  });

console.log(filtered); // ["goodpart", "goodpar2t", "goodpart3"]

如果您想按照数组元素本身进行过滤，以删除所有包含单词'nonsense'的单词：

var myarray = ["nonsense", "goodpart", "nonsense2", "goodpar2t", "nonsense3", "goodpart3"],
  filtered = myarray.filter(function(el) {
    // an indexOf() equal to -1 means the passed-in string was not found:
    return el.indexOf('nonsense') === -1;
  });

console.log(filtered); // ["goodpart", "goodpar2t", "goodpart3"]

或者只查找并保留以'good'开头的单词：

var myarray = ["nonsense", "goodpart", "nonsense2", "goodpar2t", "nonsense3", "goodpart3"],
  filtered = myarray.filter(function(el) {
    // here we test the word ('el') against the regular expression,
    // ^good meaning a string of 'good' that appears at the beginning of the
    // string:
    return (/^good/).test(el);
  });

console.log(filtered); // ["goodpart", "goodpar2t", "goodpart3"]

参考资料：

• Array.prototype.filter() 方法。
• Array.prototype.indexOf() 方法。
• 了解 JavaScript 正则表达式。
• RegExp.prototype.test() 方法。
• String.prototype.indexOf() 方法。

- David Thomas

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嗯嗯…现在我明白了，为什么会有咳咳…有趣! :) - PeterKA

抱歉，我刚意识到我没有展示其他（可能实用/相关）的方法。我想当你在写自己的答案时，我正在更新。不过，这并不是不点赞的理由 :) - David Thomas

Answer 2

这只是对@DavidThomas的伟大答案（+1）进行微小改动。 如果您决定按值（nonsense）而不是按位置（odd）排除数组成员，则此方法将非常有用：

var myarray = ["nonsense", "goodpart", "nonsense2", "goodpar2t", "nonsense3", "goodpart3"],
    filtered = myarray.filter(function(el) {
        //return only values that do not contain 'nonsense'
        return el.indexOf('nonsense') === -1;
    });

var myarray = ["nonsense", "goodpart", "nonsense2", "goodpar2t", "nonsense3", "goodpart3"],
  filtered = myarray.filter(function(el) {
    //return only values that do not contain 'nonsense'
    return el.indexOf('nonsense') === -1;
  });


//output result
$('pre.out').text( JSON.stringify( filtered ) );

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<pre class="out"></div>

- PeterKA