is_numeric in php

How to Check a Value Is Numeric in PHP

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In this tutorial, we’ll talk about how to use is numeric in PHP to check the value of a string. With the help of examples, it’s easy to figure out what is_numeric is used for.

Before we begin, if you missed any of our prior lessons, you can review the topics in our PHP Tutorial for Beginners.

Definition and Usage of is_numeric in PHP

The is_numeric() function describes whether a variable is a number or a string of numbers. If the variable is a number or a numeric string, this function returns true; otherwise, it returns false/nothing.

Additionally, based on the PHP documentation, is_numeric finds whether a variable is a number or a numeric string.

Syntax

is_numeric( variable );

Parameter Values

ParameterDescription
variableRequired. Specifies the variable to check

Technical Details

Return Value:TRUE if variable is a number or a numeric string, FALSE otherwise
Return Type:Boolean
PHP Version:4.0+

Is_numeric PHP examples

The following is an example usage of is_numeric:

<?php
    // if it is a number
    $str = "050122";
    if ( is_numeric($str) ) {
        echo "'{$str}' is a numeric.";
    } else {
        echo "'{$str}' is not a numeric.";
    }
    
    echo ("\n");
    
    // if it is a string
    $str = "itsourcecode";
    if ( is_numeric($str) ) {
        echo "'{$str}' is a numeric.";
    } else {
        echo "'{$str}' is not a numeric.";
    }
?>

Output

'050122' is a numeric.
'itsourcecode' is not a numeric.

Explanation

The example above illustrates that if the value of a $str value is a number, it will print that it is numeric. If it is a string, then it will print that it is not numeric.

Is_numeric PHP examples with whitespace

The following is an example usage of is_numeric, but this time, the value of the string has whitespace:

<?php
    // if it is a number
    $str = "05 01 22";
    if ( is_numeric($str) ) {
        echo "'{$str}' is a numeric.";
    } else {
        echo "'{$str}' is not a numeric.";
    }
    
    echo ("\n");
    
    // if it is a string
    $str = "it source code";
    if ( is_numeric($str) ) {
        echo "'{$str}' is a numeric.";
    } else {
        echo "'{$str}' is not a numeric.";
    }
?>

Output

'05 01 22' is not a numeric.
'it source code' is not a numeric.

Explanation

The example above illustrates that if the value of a $str value is a number with whitespace, it will print that it is not numeric. Therefore, if the variable value has whitespace on it, it will return a value of False.

Frequently Ask Question

What is_numeric value in PHP?

PHP has a lot of built-in functions that can be used to check the type of data in a variable. One of them is called is numeric(). It is used to see if a variable or a string of numbers is a number or a number.

Along with the digits, the string of numbers can have the “+/-” symbol, a decimal point, and an exponential part. This tutorial shows how this function can be used for different things in PHP.

Is_numeric array PHP?

With a numeric array, we can store more than one value of the same type in a single variable instead of making a new variable for each value. The index, which is always a number in a numeric array, can then be used to get to these values.

Note: The index always starts at 0 by default.

Is a function a numeric?

Returns a Boolean value that says whether an expression can be evaluated as a number. The required expression argument is a Variant with a string or numeric expression.

Summary

To summarize, we now understand exactly how to use is_numeric. I hope this tutorial has helped you understand the meaning and application of is_numeric in PHP.

Lastly, if you want to learn more about is_numeric in PHP, please leave a comment below. We’ll be happy to hear it!

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