In string n+n(n+n), where n stands for any number or digit, I'd like to match ( and replace it by *(, but only if it is followed by a number or digit.
Examples:
2+22(2+2) into 2+22*(2+2),-1(3) into -1*(3),4+(5/6) should stay as it is.This is what I have:
var str = '2+2(2+2)'.replace(/^[0-9]\(/g, '*(');
But it doesn't work. Thanks in advance.
Remove the ^, and group the digits:
'2+2(2+2)'.replace(/([0-9])\(/g, '$1*(')
'2+2(2+2)'.replace(/(\d)\(/g, '$1*(') //Another option: [0-9] = \d
Suggestion: 2. is often a valid number (= 2). The following RegExp removes a dot between a number and a parenthesis.
'2+2(2+2)'.replace(/(\d\).?\(/g, '$1*(') //2.(2+2) = 2*(2+2)
Parentheses create a group, which can be referenced using $n, where n is the index of the group: $1.
You started your RegExp with a ^..., which means: Match a part of the string which starts with .... This behaviour was certainly not intended.
[0-9] and \d
var str = '2+2(2+2)+3(1+2)+2(-1/2)'.replace(/([0-9])\(/g, '$1*(');
This follows what you wrote (the bracket must follow a number).
So 4( will be changed to 4*( it could be important for example for 4(-1/2)
