JavaScript:查找字符串中最大的单词

Question

这是我的片段。我觉得这段代码满足算法，但没有通过。可能的原因是什么？

function findLongestWord(str, separator) {
    var splitString = str.split(separator);
    for (var i = 1; i <= splitString.length; i++) {
        for (j = 1; j < splitString[i].length; j++) {
            while (j === ' ') {
                return j;
            }
        }
    }
    var greater;
    if (j > greater) {
        greater = j;
    }
    return greater;
}

findLongestWord("The quick brown fox jumped over the lazy dog", ' ');

Answer 1

这是您的代码，附有说明和一些使其正常工作的更改

function findLongestWord(str, separator) {
    var splitString = str.split(separator);

    // Define it as empty string
    var greater = '';

    // Start looping from 0th index upto the length
    for (var i = 0; i < splitString.length; i++) {
        for (j = 0; j < splitString[i].length; j++) {
            // Don't know what this is
            // `j` is the index, i.e. number, it cannot be equal to ` `
            // I guess this is confused with the separator

            // This can be removed without any problem
            while (j === ' ') {
                return j;
            }
            // No use code
        }
        // Here `j` is the length of the word
        // Compare it with the length of greater word
        if (j > greater.length) {
            // Update the greater to current `i` string
            greater = splitString[i];
        }
    }

    // Return greater string.
    return greater;
}

var longestWord = findLongestWord("The quick brown fox jumped over the lazy dog", ' ');
document.body.innerHTML = 'Longest Word: ' + longestWord;

<小时/>

经过很少优化的相同代码可以重写为

function findLongestWord(str, separator) {
    var splitString = str.split(separator);
    // Define it as empty string
    var greater = '';

    for (var i = 0, len = splitString.length; i < len; i++) {
        if (splitString[i].length > greater.length) {
            // Update the greater to current `i` string
            greater = splitString[i];
        }
    }

    return greater;
}

var longestWord = findLongestWord("The quick brown fox jumped over the lazy dog", ' ');
document.body.innerHTML = 'Longest Word: ' + longestWord;
console.log(longestWord);

我使用 ES6 的解决方案

您可以使用Array#reduce和 Arrow functions 。对于 ES5 中的相同代码，请检查 this answer通过 @gurvinder372

str.split(' ').reduce((x, y) => x.length > y.length ? x : y);

function findLongestWord(str, separator) {
    return str.split(' ').reduce((x, y) => x.length > y.length ? x : y);
}

var longestWord = findLongestWord("The quick brown fox jumped over the lazy dog", ' ');
document.body.innerHTML = 'Longest Word: ' + longestWord;
console.log(longestWord);