jQuery中的$ .map和$ .grep有什么区别

What is the difference between $.map and $.grep in jQuery?

jQuery中$ .map和$ .grep有什么区别?

I want a simple answer as far as possible.

我想尽可能简单的回答。

2 个解决方案

#1

I will assume you mean $.grep and $.map. The difference is that we use $.grep to filter an array while we use $.map to apply a function to each item in the array.

我假设你的意思是$ .grep和$ .map。不同之处在于我们使用$ .grep来过滤数组,而我们使用$ .map将函数应用于数组中的每个项目。

Here is a much better explanation than I can make:

这是一个比我能做的更好的解释:

http://onwebdev.blogspot.com/2011/03/jquery-grep-and-map-example-and-syntax.html

#2

$.map method can be used as an iterator, but is meant to manipulate the array and return a new array.

$ .map方法可以用作迭代器,但是用于操作数组并返回一个新数组。

var items = ['A','B','C','A'];    

var items = $.map(items, function(item) {
  if (item == 'A') 
    return null;
  return item;
});

items is now new array. ['B','C']

items现在是新数组。 ['公元前']

var items = $.map(items, function(item) {
  if (item == 'A') 
    return 'A'+'B';
  return item;
});

output will be ['AB', 'B', 'C', 'AB']

输出将是['AB','B','C','AB']

$.grep is used for filtering

$ .grep用于过滤

var items = $.grep(items, function(item) {
      return item != 'A';
    });

items is now ['B','C']

物品现在是['B','C']

however

var items = $.grep(items, function(item) {
      if (item == 'A') 
        return 'A'+'B';
      return item;
    })

will return ['A', 'B', 'C', 'A'] as it is not producing new stuff - it reduces the existing.

将返回['A','B','C','A'],因为它不会产生新的东西 - 它会减少现有的东西。

#1