How to ignore digits that start with 0 (zero) using regular expression?

Question

I'm trying to match digits but I need to follow some rules.
The digits may (or may not) start with a sign [+-].
If the digits start with a 0 it can NOT be followed by anything.
But if it's 0 by itself, it should be matched.

I came up with the following regular expression:

[+-]*[1-9]\d*|[+-]*[0](?!\w)

But it's not working exactly as I need:

01 (matches 1, should match nothing)
9,000 (matches 9 and last 0, should match 9 only)
+0152 (matches 152, should match nothing)
-1200 (matches -1200, working as intended)
+0 (matches +0, working as intended)

Live demostration

Answer 1

You can use this regex:

[+-]?\b(?:0|[1-9][0-9]*)\b

RegEx Demo

RegEx Breakup:

• [+-]? - Match + or - optionally first
• \b - Assert a word boundary
• (?: - Start a non-capturing group
  • 0 - Match a single 0
  • | - OR
  • [1-9][0-9]* - Match 1-9 followed by any digit 0 or more times
• ) - End non-capturing group
• \b - Assert word boundary

Answer 2

Try the following Regex:

^[+-]?[1-9]\d*|[+-]*[0](?!\w)$

• You don't need * after [+-] as it will match many signs, use ? instead.
• And you will need to wrap your regex between ^ and $ so it matches the whole matching regex and giva wanted matches in your cases.

Edit:

You will need to use word boundary \b instead of ^ and $, if you are dealing with words and not lines.