What is the regex for ascii only string?

The regex pattern for ascii only string is `^[\x00-\x7F]+$`. This pattern validates string containing only ascii characters (0-127).

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^[\x00-\x7F]+$/;` 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'^[\x00-\x7F]+$', 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 (`/^[\x00-\x7F]+$/i`) or use `re.IGNORECASE` in Python.

Regex for ASCII Only String

Regex Pattern

^[\x00-\x7F]+$

String containing only ASCII characters (0-127)

Quick Answer

The regex pattern for ascii only string is `^[\x00-\x7F]+$`. String containing only ASCII characters (0-127). This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
Hello World	✓ Matches
abc123!@#	✓ Matches
ASCII only	✓ Matches
Café	✗ No match
üöä	✗ No match
你好	✗ No match

Code Examples

javascript

const regex = /^[\x00-\x7F]+$/;
const isValid = regex.test(value);

python

import re
pattern = r'^[\x00-\x7F]+$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^[\x00-\x7F]+$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^[\x00-\x7F]+$/', $value)) {
    echo "valid";
}

java

String pattern = "^[\\x00-\\x7F]+$";
boolean isValid = value.matches(pattern);

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