Question

我需要根据单词数量以升序排列打印输入字符串。我试过这段代码！

我的问题是，如何根据count值对元素进行排序？即应首先显示较大的count值单词（count值的降序）？

Javascript文件，app.js：

var x = stringCount("this is my file teting the things apple teting this is my the is is is is ", ' ');
console.log(x);

function stringCount(haystack, needle) {
    if (!needle || !haystack) {
        return false;
    }
    else {
        var words = haystack.split(needle),
            count = [];
        for (var i = 0, len = words.length; i < len; i++) {
            if (count.hasOwnProperty(words[i])) {
                count[words[i]] = parseInt(count[words[i]], 10) + 1;
            }
            else {
                count[words[i]] = 1;
            }
        }
        count.sort();
        return count;

    }
}

这是输出我得到的。

[ this: 2,
  is: 6,
  my: 2,
  file: 1,
  teting: 2,
  the: 2,
  things: 1,
  apple: 1,
  '': 1 ]

Answer 1

变化：

    return count;

为：

    return Object.keys(count).map(k => [k, count[k]])
        .sort((a, b) => a[1] < b[1]).map(e => e[0]);

Answer 2

您的count变量是一个对象。虽然您将其定义为数组，但它不是真正的数组元素，而是字属性。所以你实际上正在排序一个空数组。

以下是如何调整代码以使其正常工作的方法：

var x = stringCount("this is my file teting the things apple teting this is my the is is is is ", ' ');
console.log(x);

function stringCount(haystack, needle) {
    if (!needle || !haystack) {
        return false;
    }
    else {
        var words = haystack.split(needle).filter(x => x), // filter out empty words
            count = {}; // not an array
        for (var i = 0, len = words.length; i < len; i++) {
            if (count.hasOwnProperty(words[i])) {
                count[words[i]] = parseInt(count[words[i]], 10) + 1;
            }
            else {
                count[words[i]] = 1;
            }
        }
        return Object.keys(count) // array of words
                .sort( (a,b) => count[b] - count[a] ); // sort by count
    }
}

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Answer 3

您可以按值对键进行排序。

function stringCount(haystack, needle) {
    if (!needle || !haystack) {
        return false;
    }
    var words = haystack.split(needle),
        count = {};
    words.forEach(function (a) {
        count[a] = (count[a] || 0) + 1;
    });
    return count;
}

var x = stringCount("this is my file teting the things apple teting this is my the is is is is ", ' ');

console.log(x);
console.log(Object.keys(x).sort(function (a, b) { return x[b] - x[a]; }));

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如何根据计数值对单词进行排序：javascript

3 个答案: