I have a string which has a character (\n) repeated multiple times. I want to replace this repetitions by just one repetition less.

So let's suppose that we have a string like this (\n repeats 3 times)

hello\n\n\ngoodbye

Ans I want to convert it to this (\n repeats 2 times)

hello\n\ngoodbye

I know how to find out with regex when the occurrence repeats (e.g. /\n\n /g), but I don't know how to capture the exact number of repetitions to use it in the replace.

Is possible to do that with Regex?

CodePudding user response：

You can search using this regex:

/\n(\n*)/g

And replace using: $1

RegEx Demo

RegEx Details:

• \n: Match a line break
• (\n*): Match 0 or more line breaks and capture them in 1st capture group. Note that we are capturing one less \ns in this capture group
• Replacement of $1 will place all \ns with back-reference of 1st capture group, thus reducing line breaks by one.

Code:

const string = 'hello\n\n\ngoodbye';
console.log(string);

const re = /\n(\n*)/g;
var repl = string.replace(re, "$1");

console.log(repl);

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

CodePudding user response：

replace (\n*)\n with $1?

let str = 'hello\n\n\ngoodbye'
console.log(str)
console.log(str.replace(/(\n*)\n/,'$1'))

<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>