如何使用javascript替换字符串中最后匹配的字符 [英] How to replace last matched character in string using javascript

问题描述

我想将键盘上的最后一个输入字符替换为''

i want to replace last input character from keyboard to ''

我的字符串输入是

示例字符串

"<p><strong>abscd sample text</strong></p>"

"<p>abscd sample text!</p>"

我的最后一个角色是动态的，可以是介于两者之间的任何东西a 到 z、A 到 Z、0 到 9、任何特殊字符([~/< > & ( . ] ).所以我只需要替换那个字符

My last character is dynamic that can be any thing between a to z, A to Z, 0 to 9, any special characters([~ / < > & ( . ] ). So i need to replace just that character

例如在示例 1 中我需要替换t"，而在示例 2 中需要替换！"

for example in Sample 1 i need to replace "t" and in sample 2 in need to replace "!"

我尝试了以下代码.但它对我不起作用

I tried below code. but it id not worked for me

 var replace = '/'+somechar+'$/';

有什么办法吗?

推荐答案

第一步

替换字符串中的a字符，使用javaScript的replace()函数.这里是 MDN 规范:

Step one

to replace the a character in a string, use replace() function of javaScript. Here is the MDN specification:

返回一个新字符串，其中部分或全部模式匹配项被替换项替换.模式可以是字符串或正则表达式，替换可以是字符串或每次匹配时调用的函数.

Returns a new string with some or all matches of a pattern replaced by a replacement. The pattern can be a string or a RegExp, and the replacement can be a string or a function to be called for each match.

第二步

您需要通过正则表达式定位要替换的字符.您想替换字符串的最后一个字符，这可以表示为/(.+)(.)$/.. 代表任意字符，+ 表示多个字符.这里 (.+) 匹配最后一个之前的所有字符.(.) 匹配最后一个字符.

Step two

you need to location the character to be replaced through regular expression. You want to replace the last character of a string and this could be expressed as /(.+)(.)$/. . stands for any character, + means more than one character. Here (.+) matches all the character before the last one. (.) matches the last character.

您要替换的是第二个括号内的那个.因此，您使用与 $1 匹配的第一个括号中的相同字符串并替换其后的任何内容.

What you want to replace is the one inside the second brackets. Thus you use the same string matched in the first bracket with $1 and replace whatever after it.

这是实现您的意图的代码:

Here is the code to realize your intention:

text = 'abscd sample text';
text.replace(/(.+)(.)$/, '$1!');

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