Javascript：在字符串中找到最长的单词

Javascript: find longest word in a string

提问by bard

function longestWord(string) {
    var str = string.split(" ");
    var longest = 0;
    var word = null;
    for (var i = 0; i < str.length - 1; i++) {
        if (longest < str[i].length) {
            longest = str[i].length;
            word = str[i];
        }
    }
    return word;
}

When I call longestWord("Pride and Prejudice"), it returns 'Pride' and not 'Prejudice' which is the longest word... why? I checked some other similar questions, but the solutions looked a lot like my code.

当我打电话时longestWord("Pride and Prejudice")，它返回“傲慢”而不是“偏见”，这是最长的词......为什么？我检查了一些其他类似的问题，但解决方案看起来很像我的代码。

回答by Musa

That's because you're not comparing all the items in the array, you leave out the last one.

那是因为您没有比较数组中的所有项目，而忽略了最后一个。

for (var i = 0; i < str.length - 1; i++)

should be

应该

for (var i = 0; i < str.length; i++)

or

或者

for (var i = 0; i <= str.length - 1; i++)

回答by merv

One advantage to taking a functional approach to such problems is that you don't even have to keep count

对此类问题采用函数式方法的一个优点是，您甚至不必计算

See MDN Array.reducefor more info. (note: reduceneeds shim for IE8)

有关更多信息，请参阅MDN Array.reduce。（注意：reduceIE8 需要垫片）

function longer(champ, contender) {
  return (contender.length > champ.length) ? contender : champ;
}

function longestWord(str) {
  var words = str.split(' ');
  return words.reduce(longer);
}

console.log(longestWord("The quick brown fox jumped over the lazy dogs"));

回答by aaronman

Here this is your solution with a forEach, this will help you avoid the error in the future

这是您使用 forEach 的解决方案，这将帮助您避免将来出现错误

function longestWord(string) {
    var str = string.split(" ");
    var longest = 0;
    var word = null;
    str.forEach(function(str) {
        if (longest < str.length) {
            longest = str.length;
            word = str;
        }
    });
    return word;
}
console.log(longestWord("pride and prejudice"));

Your original problem was just the str.length - 1should have just been str.length, originally you wouldn't have gotten to the last element of the array

你原来的问题只是str.length - 1本来应该是str.length，原来你不会得到数组的最后一个元素

回答by tymeJV

You have a -1in your condition, it never even scans it:

你的情况有一个-1，它甚至从不扫描它：

for (var i = 0; i < str.length - 1; i++) {

Should be:

应该：

for (var i = 0; i < str.length; i++) {

Demo: http://jsfiddle.net/LfgFk/

演示：http: //jsfiddle.net/LfgFk/

回答by acdcjunior

The index is going up to str.length -1:

指数上升至str.length -1：

for (var i = 0; i < str.length - 1; i++) {

So the last word is not processed.

所以最后一个字没有被处理。

Try with: longestWord("Pride AAAAAAAAAAAAAAAAAAAAAAAAA and Prejudice"). You'll see it works (returns AAAAAAAAAAAAAAAAAAAAAAAAA).

尝试：longestWord("Pride AAAAAAAAAAAAAAAAAAAAAAAAA and Prejudice")。你会看到它起作用（返回AAAAAAAAAAAAAAAAAAAAAAAAA）。

In case you're in doubt, the simplest way to fix it is removing the -1from the forloop.

如果您有疑问，修复它的最简单方法是-1从for循环中删除。

for (var i = 0; i < str.length; i++) {

Check a demo with both versions (the problematic and the fixed): link here.

检查两个版本（有问题的和已修复的）的演示：链接在这里。

回答by Gergo Erdosi

You can simplify your code with a library like Lo-Dash:

您可以使用Lo-Dash 之类的库来简化代码：

function longestWord(string) {
    var words = string.split(' ');
    return _.max(words, function(word) { return word.length; });
}

回答by Shushanth Pallegar

ForEach is faster in FF but slower in Chrome, but for loop with the cached length and function apply/call is quite faster in both FF and chrome.

ForEach 在 FF 中更快，但在 Chrome 中更慢，但是具有缓存长度和函数应用/调用的 for 循环在 FF 和 chrome 中都更快。

Hope the below code helps:

希望下面的代码有帮助：

function getLongest (arrStr) {
  var longest = 0, word;

  for(var i=0 , len = arrStr.length ; i < len ; i++){

    if(longest < arrStr[i].length) {
       longest = arrStr[i].length;
       word = arrStr[i];
    }

  }

  return word;
}

function isLongest (str) {
  var arrayStr = str.split(' ');
  return function(fn) {
    return fn.apply(this,[arrayStr]);
  }
}

isLongest("hello aaaaaaaaaaaaaaaaaaaaaaaaa bbb")(getLongest); //aaaaaaaaaaaaaaaaaaaaaaaaa

回答by Shushanth Pallegar

does this solve the problem??

这能解决问题吗？？

function longestWord(string) {
    var str = string.split(" ");
    var longest = 0;
    var word = null;
    for (var i = 0; i <= str.length - 1; i++) {
        if (longest < str[i].length) {
            longest = str[i].length;
            word = str[i];
        }
    }
    return word;
}

document.write(longestWord("pride and prejudice"));

回答by Bekzat

function longestWord(sentence){
 var arr = sentence.match(/[a-z]+/gi);
 arr.sort(function(a, b){
 return b.length - a.length;
});
 return arr[0];
}
longestWord('hello man@#$%');
// ==> output: hello

回答by Cheyenne Crawford

I find that the .map method here helps a lot (this is if you want the character count of the word, not the word itself):

我发现这里的 .map 方法有很大帮助（这是如果您想要单词的字符数，而不是单词本身）：

 function findLongestWord(str) {   
   var array = str.split(/\s+/);
   var wordLength = array.map(function(i) {
     return i.length;                       
   });   
   var largest = Math.max.apply(Math, wordLength);   
   return largest; 
}