Question

I need to find a line from a file and replace it:

Suppose this the content in the file: ‘547714,0,1,1,0,1,1,0,0,0,0,0,0,0,0,0’

Based on 547714 i need to select and replace the complete line

i am using this regexp: '/^.*547714.*$/';

But its not selecting anything.

Answer 1

The regex looks OK. However, you need to tell the regex engine to allow the ^ and $ anchors to match the start and end of each line (and not the entire input string). That’s what the /m modifier is for. Also, word boundaries (\b) are a good idea here to avoid substring matches.

So I’d suggest

regex = '/^.*\b345345\b.*$/m';

This will match an entire line containing 345345 (but it won’t match a line like 1,53453456,4,5,0).