What is the regex for query parameter?

The regex pattern for query parameter is `[?&]([a-zA-Z0-9_]+)=([^&#]*)`. This pattern validates extracts key-value pairs from url query strings.

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /[?&]([a-zA-Z0-9_]+)=([^&#]*)/;` 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'[?&]([a-zA-Z0-9_]+)=([^&#]*)', 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 (`/[?&]([a-zA-Z0-9_]+)=([^&#]*)/i`) or use `re.IGNORECASE` in Python.

Regex for Query Parameter

Regex Pattern

[?&]([a-zA-Z0-9_]+)=([^&#]*)

Extracts key-value pairs from URL query strings

Quick Answer

The regex pattern for query parameter is `[?&]([a-zA-Z0-9_]+)=([^&#]*)`. Extracts key-value pairs from URL query strings. This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
?name=John	✓ Matches
?foo=bar&baz=qux	✓ Matches
url?key=value	✓ Matches
no-query	✗ No match
example.com	✗ No match
#fragment	✗ No match

Code Examples

javascript

const regex = /[?&]([a-zA-Z0-9_]+)=([^&#]*)/;
const isValid = regex.test(value);

python

import re
pattern = r'[?&]([a-zA-Z0-9_]+)=([^&#]*)'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /[?&]([a-zA-Z0-9_]+)=([^&#]*)/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/[?&]([a-zA-Z0-9_]+)=([^&#]*)/', $value)) {
    echo "valid";
}

java

String pattern = "[?&]([a-zA-Z0-9_]+)=([^&#]*)";
boolean isValid = value.matches(pattern);

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