What is the regex for non-negative integer?

The regex pattern for non-negative integer is `^(0|[1-9]\d*)$`. This pattern validates zero or positive integer.

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^(0|[1-9]\d*)$/;` and test with `regex.test(yourValue)`. It returns `true` if the value matches.

How do I use this regex in Python?

In Python, use `import re; re.match(r'^(0|[1-9]\d*)$', value)`. The raw string prefix (`r`) prevents Python from interpreting backslashes as escape characters.

Is this regex case-sensitive?

By default, yes. To make it case-insensitive, add the `i` flag in JavaScript (`/^(0|[1-9]\d*)$/i`) or use `re.IGNORECASE` in Python.

Regex for Non-negative Integer

Regex Pattern

^(0|[1-9]\d*)$

Zero or positive integer

Quick Answer

The regex pattern for non-negative integer is `^(0|[1-9]\d*)$`. Zero or positive integer. This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
0	✓ Matches
1	✓ Matches
42	✓ Matches
100	✓ Matches
-1	✗ No match
1.5	✗ No match
01	✗ No match
abc	✗ No match

Code Examples

javascript

const regex = /^(0|[1-9]\d*)$/;
const isValid = regex.test(value);

python

import re
pattern = r'^(0|[1-9]\d*)$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^(0|[1-9]\d*)$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^(0|[1-9]\d*)$/', $value)) {
    echo "valid";
}

java

String pattern = "^(0|[1-9]\\d*)$";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

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