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In-depth understanding of JS regular expression range class analysis

不言
不言Original
2018-07-11 09:34:011789browse

This article mainly introduces the analysis of range classes for in-depth understanding of JS regular expressions. It has certain reference value. Now I share it with you. Friends in need can refer to it

Range classes

When using regular expressions, many times we want to match all letters from a~z. Many people think of using the character class [abcdefg...z] , however, this method requires entering all the letters that need to be matched. So, is there a simpler way?

Fortunately, regular expressions provide a range class, which allows us to use [a-z] to connect two characters to represent any character from a to z.

Basic usage

let text = 'a1b2d3x4z5'

let reg = /[a-z]/g

text.replace(reg, 'Q')  // Q1Q2Q3Q4Q5

tips: It is worth noting that the range class is a closed interval, that is: [a-z]includes a and z

range Concatenation of classes

There is a little trick when using range classes: you can concatenate within a class composed of [], for example: [a-zA-Z]

let text = 'a1B2d3X4Z5'

let reg = /[a-zA-Z]/g

text.replace(reg, 'Q')  // Q1Q2Q3Q4Q5

The above is the entire content of this article. I hope it will be helpful to everyone's study. For more related content, please pay attention to the PHP Chinese website!

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