JavaScript字符串匹配方法快速指南

快来打我* 2022-11-27 04:27 199阅读 0赞

`String.prototype.match()` (aka: the match method on strings) can allow you to switch out strings or set conditions if a string or any data is matched. It then stores that data in a new array.

`String.prototype.match()` (又名：字符串的match方法)可以让您在匹配字符串或任何数据时切换出字符串或设置条件。 然后，它将数据存储在新数组中。

First the syntax and then the explanation:

首先是语法，然后是解释：

let newArray = string.match(condition);

## 术语 **(**Terminology**)** ##

The string `match()` method will return an array with the items being matches from a provided `regular expression` found in the string. You can [read more about regular expressions in JavaScript here][].

字符串`match()`方法将返回一个数组，其中的项与字符串中提供的`regular expression`的项匹配。 您可以[在此处阅读有关JavaScript中正则表达式的更多信息][read more about regular expressions in JavaScript here] 。

Remember, when all conditions are matched, those results will be stored in a new **array**.

请记住，当所有条件都匹配时，这些结果将存储在新**数组中** 。

Take the following example:

请看以下示例：

const intro = "Hello Alligators, Hello Devs, how are you?"
    
    const regex = /Hello/g;
    
    const greeting = intro.match(regex);

The above will give us an array like this: `["Hello", "Hello"]`. This works fine if we know the exact string we’re looking to match, but what about dynamic content or an actual use case?

上面的代码将给我们这样的数组： `["Hello", "Hello"]` 。 如果我们知道要查找的确切字符串，则此方法很好，但是动态内容或实际用例呢？

Here’s a simple example that finds repeated letters in a string:

这是一个简单的示例，可在字符串中查找重复的字母：

const str = 'See you later, Alligator! Not so soon baboon!';
    const matches = str.match(/([a-z])\1+/gi);
    
    console.log('H' + matches.join(""));
    // "Heelloooo"

Though these are simple examples, the deeper you learn about regular expressions, the more powerful this string method becomes. The simple use of `i` for insensitive case allows the match method to highlight more entries.

尽管这些都是简单的示例，但是您对正则表达式的了解越深，这种字符串方法就越强大。 不区分大小写的`i`的简单用法允许match方法突出显示更多条目。

--------------------

The match method has 3 modes…

匹配方法有3种模式…

*  **1st**: If the `g`(global) flag is used for your RegEx, you’ll get all results stored in an array.
    
    **1st** ：如果将`g` (全局)标志用于RegEx，则将所有结果存储在数组中。
 *  **2nd**: If there are no `g` flag used, the first match will return an array with keys/values sharing index of the first matched expression, the full input and then the capturing groups. In other words, the same result as with using `RegExp.exec()`.
    
    **2nd** ：如果没有使用`g`标志，则第一个匹配项将返回一个数组，该数组包含第一个匹配表达式的键/值共享索引，完整输入以及捕获组。 换句话说，与使用`RegExp.exec()`结果相同。

let newYear = "Happy New Year";
    let results = newYear.match(/new/i);
    // [ 'New', index: 6, input: 'Happy New Year', groups: undefined ]

*  **3rd**: If there’s no match, the method returns `null`, or, with the following code, an empty array:
    
    **3rd** ：如果不匹配，则该方法返回`null` ，或者使用以下代码返回一个空数组：

let results = newYear.match(regex) || [];

## 结论 **(**Conclusion**)** ##

Match is a fun little method that can be used in a lot of creative ways like pulling out keywords from a paragraph or replacing words if the condition matches the regex. Take the time to learn about Regular Expressions in JavaScript. It’ll make match even more useful for you.

匹配是一种有趣的小方法，可用于许多创造性方式，例如从段落中提取关键字或在条件与正则表达式匹配时替换单词。 花时间学习JavaScript中的正则表达式 。 它会使匹配对您更有用。

> 翻译自: [https://www.digitalocean.com/community/tutorials/js-string-match][https_www.digitalocean.com_community_tutorials_js-string-match]

[read more about regular expressions in JavaScript here]: https://www.digitalocean.com/community/tutorials/js-regular-expressions-for-regular-people
[https_www.digitalocean.com_community_tutorials_js-string-match]: https://www.digitalocean.com/community/tutorials/js-string-match