TypeScript 字符串替换为正则表达式、组和部分字符串
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TypeScript string replace with regex, groups and partial string
提问by Rafael
I want to use regex to format a number inside an input as I type it.
My problem is: Since I'm using groups to format the number, it only formats when the string matches the regex.
Here's an example:
The full number is: 12312312312| Formatted would look like: 123.123.123-12.
我想在输入时使用正则表达式来格式化输入中的数字。
我的问题是：由于我使用组来格式化数字，因此它仅在字符串与正则表达式匹配时进行格式化。这是一个例子：
完整的数字是：12312312312| 格式化后看起来像：123.123.123-12.
If I type 1231231for example, it doesn't formats to 123.123.1as I was expecting, only if I type the entire number.
1231231例如，如果我输入，它不会123.123.1按照我的预期格式化，只有当我输入整个数字时。
This is my function:
这是我的功能：
format(value){
// This function returns the formatted string on user input
return value.replace(/(\d{3})(\d{3})(\d{3})(\d+)/, "$1.$2.$3-$4");
}
Is there any way to make the remaining groups optionals?
有什么办法可以让剩余的组成为可选项？
回答by marvel308
You can do it using
你可以使用
function formatStr(str){
str = str.replace(/(\d{1,3})(\d{0,3})(\d{0,3})(\d{0,2})/g, function(a, b, c, d, e){
let ret = "";
if(b != "")
ret = b;
if(c != "")
ret = ret+"." + c;
if(d != "")
ret = ret+"." + d;
if(e != "")
ret = ret+"-" + e;
return ret;
})
console.log(str);
}
formatStr('12312312312');
formatStr('1231231');回答by anubhava
You can use this formatfunction with 2 calls to .replace:
您可以format通过 2 次调用使用此函数.replace：
- First we insert a dot after every 3 digits
- Second we replace 3rd dot with hyphen
- 首先我们在每 3 位数字后插入一个点
- 其次，我们用连字符替换第三个点
Code:
代码：
function format(value) {
// This function returns the formatted string on user input
return value.replace(/(\d{3})/g, '.')
.replace(/((?:\d{3}\.){2}\d{3})\./, '-');
}
console.log(format('1231231')); //=> 123.123.1
console.log(format('12312312312')); //=> 123.123.123-12