/ \s / g和/ \s + / g之间有区别吗？ [英] Is there a difference between /\s/g and /\s+/g?

问题描述

当我们有一个包含空格字符的字符串时：

When we have a string that contains space characters:

var str = '  A B  C   D EF ';

我们想从字符串中删除空格（我们想要这个： 'ABCDEF'）。

and we want to remove the spaces from the string (we want this: 'ABCDEF').

这两个：

str.replace(/\s/g, '')

并且：

str.replace(/\s+/g, '')

将返回正确的结果。

这是否意味着 + 在这种情况下是多余的？在这种情况下，这两个正则表达式之间是否存在差异（例如，它们是否会以任何方式产生不同的结果）？

Does this mean that the + is superfluous in this situation? Is there a difference between those two regular expressions in this situation (as in, could they in any way produce different results)?

更新：效果比较 - / \s + / g 更快。请参阅此处： http://jsperf.com/s-vs-s

Update: Performance comparison - /\s+/g is faster. See here: http://jsperf.com/s-vs-s

推荐答案

在第一个正则表达式中，每个空格字符正逐字符替换，空字符串。

In the first regex, each space character is being replaced, character by character, with the empty string.

在第二个正则表达式中，空格字符的每个连续字符串由于 + 而被替换为空字符串。

In the second regex, each contiguous string of space characters is being replaced with the empty string because of the +.

但是，就像0乘以其他任何值为0一样，似乎两种方法都以完全相同的方式去除空格。

However, just like how 0 multiplied by anything else is 0, it seems as if both methods strip spaces in exactly the same way.

如果您将替换字符串更改为'＃'，差异会变得更加清晰：

If you change the replacement string to '#', the difference becomes much clearer:

var str = '  A B  C   D EF ';
console.log(str.replace(/\s/g, '#'));  // ##A#B##C###D#EF#
console.log(str.replace(/\s+/g, '#')); // #A#B#C#D#EF#

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