javascript - 从多个字符串中仅保留一个字符串 - 数组

Question

我只需要从数组中保留一个字符串:

var string = "dog";

var array = ["dog","cat","bird","snake","tiger","dog", "dog", "cat"];

好吧，为什么我多次写“狗”，这看起来很愚蠢，但这只是一个例子。

实际上，它会根据输入标签创建一个数组。像这样:

  firstEntry = true;

  inputValue = inputfield.value;

  if(inputValue != ''){
      if(firstEntry){
      inputArray.push(inputValue);
      firstEntry = false;
  }

//And know it should leave only one String

  inputValueSplit = inputValue.split(/ /g);
  removeFromArray(inputValueSplit,'');//This is a external function, (deletes empty Strings)
  inputArray = inputValueSplit;


  inputArray.filter(inputValue); // Here it should leave only one 
                                 // String of multiple Strings from
                                 // same value.

我在此处或 Google 中没有找到任何内容..

Answer 1

不知道你的意思。如果您需要一个仅包含初始数组中“dog”值的数组，则可以使用 Array.filter:

var dogs = ["dog","cat","bird","snake","tiger","dog", "dog", "cat"]
            .filter( function(a){ return a == this; }, 'dog' );
//=> ['dog','dog','dog']

如果您想从初始数组中删除双“dog”值:

var singleout = 'dog'
   ,dogs = (["dog","cat","bird","snake","tiger","dog", "dog", "cat"]
            .filter( function(a){ return a != this }, singleout ));
// now dogs contains no 'dog' value, so add 'dog' to it again
dogs.push(singleout);
//=> ["cat", "bird", "snake", "tiger", "cat", "dog"]

不使用过滤器，这是从数组中删除 double 值的通用方法:

function noDoubles(arr) {
  var doubleChk = {}, noDoubles = []; 
  for (var i=0;i<arr.length;i+=1) { doubleChk[arr[i]] = true; }
  for (var l in doubleChk) { noDoubles.push(l); }
  return noDoubles;
}
noDoubles(["dog","cat","bird","snake","tiger","dog", "dog", "cat"]);
//=> ["dog", "cat", "bird", "snake", "tiger"]

最后，从前面的函数中学习并使用 Array.filter 后，从 Array 中删除 double 可以非常简单:

function noDoubles(arr) {
  return arr.filter(function(val) {
     return !this[val] ? ((this[val] = true), true) : false;
    }, {} );    
 }
noDoubles(["dog","cat","bird","snake","tiger","dog", "dog", "cat"]);
//=> ["dog", "cat", "bird", "snake", "tiger"]

参见MDN对于 Array.filter 方法。链接的页面还包含一个填充程序，可以在旧版浏览器中启用该方法。