Get the contents with the brackets using regular expression

Question

I am new to regular expressions. I am trying to get the contents within the brackets using regex

Examples

1. 7+(4*6) ---> (4*6)
2. (44/(2*( 1 + 3))) ----> ( 1 + 3)
3. (54-(23+12)) ----> (23+12)

So, my expected output starts with ( followed by digit followed by space(may be not) followed by any of the four operators (+,-,*,/) followed by space(may be not) followed by ).

Thanks in advance...

Answer 1

Try this:

\( *\d+ *[-+*/] *\d+ *\)

It means:

• Match the character "(" literally.
• Match the character " " literally.
  • Between 0 and unlimited times, as many as possible, giving back as needed (greedy).
• Match a single digit 0..9
  • Between 1 and unlimited times, as many as possible, giving back as needed (greedy).
• Match the character " " literally.
  • Between 0 and unlimited times, as many as possible, giving back as needed (greedy).
• Match a single character present in the list "-+*/".
• Match the character " " literally.
  • Between 0 and unlimited times, as many as possible, giving back as needed (greedy).
• Match a single digit 0..9
  • Between 1 and unlimited times, as many as possible, giving back as needed (greedy).
• Match the character " " literally.
  • Between 0 and unlimited times, as many as possible, giving back as needed (greedy).
• Match the character ")" literally.

Examples:

var regExp = /\( *\d+ *[-+*/] *\d+ *\)/;
"7+(4*6)".match(regExp)[0];            // "(4*6)"
"(44/(2*( 1 + 3)))".match(regExp)[0];  // "( 1 + 3)"
"(54-(23+12))".match(regExp)[0];       // "(23+12)"

Answer 2

You can use lookahead to grab inner most parentheses and enclosed text.

This regex should work:

\((?=[^(]*$)[^)]*\)

TESTING:

'7+(4*6)'.match(/\((?=[^(]*$)[^)]*\)/);
//=> ["(4*6)"]

'(44/(2*( 1 + 3)))'.match(/\((?=[^(]*$)[^)]*\)/);
//=> ["( 1 + 3)"]

'(54-(23+12))'.match(/\((?=[^(]*$)[^)]*\)/);
//=> ["(23+12)"]

Online Demo: http://regex101.com/r/fQ2iZ2

Answer 3

\.*(\([^()]*\))\.*

And your best pal.

Answer 4

try this variant

\((?!.*\().*?\)