How to check if string contains only numeric digits in PHP ?
Last Updated :
04 Jan, 2024
Given a string, the task is to check whether the string contains only numeric digits in PHP. It is a common task to verify whether a given string consists of only numeric digits in PHP. It can be useful when dealing with user input validation, form submissions, or data processing tasks where numeric values are expected.
For instance, the below examples illustrate the concept:
Input: str = "1234"
Output: true
Input: str = "GeeksforGeeks2020"
Output: false
Here, we will cover three common scenarios for checking if the string contains only numeric digits.
Using ctype_digit Function
PHP provides a built-in function called ctype_digit() that can be used to check if all characters in a string are numeric digits.
Example: This example illustrates checking if string contains only numeric digits using ctype_digit Function in PHP.
PHP
<?php
function isNumeric( $str )
{
return ctype_digit( $str );
}
$str1 = "12345" ;
$str2 = "gfg123" ;
echo isNumeric( $str1 ) ? "Numeric String" : "Non Numeric String" ;
echo "\n" ;
echo isNumeric( $str2 ) ? "Numeric String" : "Non Numeric String" ;
?>
|
Output
Numeric String
Non Numeric String
Using Regular Expressions
Regular expressions provide a powerful way to validate and manipulate strings. The preg_match() function can be used to check if a string contains only numeric digits.
Example: This example illustrates checking if string contains only numeric digits using the Regular Expressions.
PHP
<?php
function isNumeric( $str )
{
return preg_match( '/^[0-9]+$/' , $str );
}
$str1 = "12345" ;
$str2 = "abc123" ;
echo isNumeric( $str1 ) ? "Numeric String" : "Non Numeric String" ;
echo "\n" ;
echo isNumeric( $str2 ) ? "Numeric String" : "Non Numeric String" ;
?>
|
Output
Numeric String
Non Numeric String
Using is_numeric Function
The is_numeric() function in PHP checks if a variable is a numeric value or a numeric string.
Example: This example illustrates checking if string contains only numeric digits using the is_numeric Function.
PHP
<?php
function isNumeric( $str )
{
return is_numeric ( $str );
}
$str1 = "12345" ;
$str2 = "abc123" ;
echo isNumeric( $str1 ) ? "Numeric String" : "Non Numeric String" ;
echo "\n" ;
echo isNumeric( $str2 ) ? "Numeric String" : "Non Numeric String" ;
?>
|
Output
Numeric String
Non Numeric String
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