What is the regex for leading/trailing whitespace?

The regex pattern for leading/trailing whitespace is `^\s+|\s+$`. This pattern validates matches whitespace at the start or end (for trimming).

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^\s+|\s+$/;` 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'^\s+|\s+$', 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 (`/^\s+|\s+$/i`) or use `re.IGNORECASE` in Python.

Regex for Leading/Trailing Whitespace

Regex Pattern

^\s+|\s+$

Matches whitespace at the start or end (for trimming)

Quick Answer

The regex pattern for leading/trailing whitespace is `^\s+|\s+$`. Matches whitespace at the start or end (for trimming). This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
leading	✓ Matches
trailing	✓ Matches
both	✓ Matches
notrimming	✗ No match
a b	✗ No match

Code Examples

javascript

const regex = /^\s+|\s+$/;
const isValid = regex.test(value);

python

import re
pattern = r'^\s+|\s+$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^\s+|\s+$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^\s+|\s+$/', $value)) {
    echo "valid";
}

java

String pattern = "^\\s+|\\s+$";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

Related Regex Patterns

Whitespace Only

Empty string or only whitespace characters

Consecutive Spaces

Two or more consecutive whitespace characters

Trailing Whitespace

Whitespace at the end of a line (useful for linting)

Email Address

Validates a standard email address format

Email (RFC 5322 Compliant)

RFC 5322 compliant email validation with label length limits

URL (HTTP/HTTPS)

Validates HTTP and HTTPS URLs