Regular Expression for 3 digit without 000

Question

I want to write a regular expression on Google Form

First Character between 1 to 9 Second and Third any alphabets (Upper Case) and next 3 characters should be number like 541 or 001 but not 000

This expression is also taking 000

[1-9][A-Z]{2}[0-9]{3}

Answer 1

Use alternations:

[1-9][A-Z]{2}([1-9][0-9][0-9]|[0-9][1-9][0-9]|[0-9][0-9][1-9])

See regex demo

Here,

• [1-9] - matches 1 digit from 1 to 9
• [A-Z]{2} - two uppercase ASCII letters
• ([1-9][0-9][0-9]|[0-9][1-9][0-9]|[0-9][0-9][1-9]) - 3 alternatives:
  • [1-9][0-9][0-9] - 3-digit numbers starting with 1
  • [0-9][1-9][0-9] - 3-digit numbers having 1 in the middle
  • [0-9][0-9][1-9] - 3-digit numbers ending with 1

Also, see this regex demo.

Answer 2

Use a negative look-ahead to avoid the triple zero at the end:

[1-9][A-Z]{2}(?!000)[0-9]{3}

Answer 3

Using the alternation operator [1-9][1-9][1-9]|0[1-9][1-9]|00[1-9]|0[1-9]0