CODEWITHSUNDEEP
javascriptregex
Simp4Code
Simp4Code

Reputation: 1479

RegEx to match whole line after nth occurrence of a string

Long time lurker, first time poster! Thanks to anyone in advance that can help.

I'm using Node.JS and Electron to make a little desktop app that manages the values in a game file (which is from a custom file type, basically a glorified INI file). With the idea of letting people customise the file in a nice UI as opposed to combing through hundreds of lines of code. Below is a sample from the file:

setting $Low
    prop $Config A_STRING_HERE "5, 10, 15, 20"

setting $Medium
    prop $Config A_STRING_HERE "10, 20, 40, 80"

setting $High
    prop $Config A_STRING_HERE "20, 40, 80, 160"

setting $VeryHigh
    prop $Config A_STRING_HERE "40, 80, 160, 320"

How would I go about matching, for example, the "setting $High" (3rd) occurrence containing "A_STRING_HERE" until the end of the line. I'm hoping to match just:
A_STRING_HERE "20, 40, 80, 160".

The values are dynamic and will change a lot, so matching the line with the values isn't necessarily an option.

Thanks again and all the best!

Upvotes: 1

Views: 253

Answers (1)

mandy8055
mandy8055

Reputation: 6715

You can probably try this regex:

(?<=setting \$High\n\s*?prop \$Config )A_STRING_HERE.*

Explantion

  • (?<=) - Represents positive lookbehind.
  • setting \$High\n\s*?prop \$Config - The text that separates this match with other matches. You can probably omit setting part to make it more concise.
    • \n - Represents new line.
    • \s*? - Lazily matches 0 or more white spaces. You can adjust it according to your need.
  • .* - Matches everything except \n. You can be specific here as well if you want to include numbers only.
  • \g - Please note only global flag is used.

You can find the implementation of the above regex in here.

Image Explanation: Image

const regex = /(?<=setting \$High\n\s*?prop \$Config )A_STRING_HERE.*/g;

// Alternative syntax using RegExp constructor
// const regex = new RegExp('(?<=setting \\$High\\n\\s*?prop \\$Config )A_STRING_HERE.*', 'g')

const str = `setting \$Low
    prop \$Config A_STRING_HERE "5, 10, 15, 20"
setting \$Medium
    prop \$Config A_STRING_HERE "10, 20, 40, 80"
setting \$High
    prop \$Config A_STRING_HERE "20, 40, 80, 160"
setting \$VeryHigh
    prop \$Config A_STRING_HERE "40, 80, 160, 320"`;
console.log(str.match(regex)[0]);

Upvotes: 2

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