Regular expression for integer with or without commas

I want to create a regular expression for all sorts of numbers i.e whole numbers (+ve and -ve) and decimal numbers (+ve and -ve) with or without commas.

For e.g the regular expression should cover following number formats.

  111     1.11     1,111     1,111.01     1,111,111.01 
 +111    +1.11    +1,111    +1,111.01    +1,111,111.01
 -111    -1.11    -1,111    -1,111.01    -1,111,111.01

I have created two regular expressions for handling my scenario.

 "^(\\+|-)?[0-9]\\d*(\\.\\d+)?$"   // handles whole numbers with decimals
 "^(\\+|-)?[0-9]\\d*(\\,\\d+)*?$"  // handles whole numbers with commas

Now, I want to merge these two regular expressions in order to address my requirements.

Can anyone help me?
Thanks in advance.

Solution

You may merge these 2 patterns of yours like

^[+-]?[0-9]+(?:,[0-9]+)*(?:[.][0-9]+)?$

See the regex demo

Details:

^ - start of a string
[+-]? - an optional + or -
[0-9]+ - 1 or more digits
(?:,[0-9]+)* - zero or more sequences of:
- , - a comma
- [0-9]+ - 1 or more digits
(?:[.][0-9]+)? - an optional sequence of:
- [.] - a dot
- [0-9]+ - 1+ digits
$ - end of string

A more restrictive regex to only allow 3-digits in groupings will look like

^[+-]?[0-9]{1,3}(?:,[0-9]{3})*(?:[.][0-9]+)?$
           ^^^^^         ^^^

And if you want to also match whole parts with no thousand separators:

^[+-]?(?:[0-9]{1,3}(?:,[0-9]{3})*|[0-9]+)(?:[.][0-9]+)?$