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PHP String Functions

PHP Strings Functions

PHP has a lot of string functions. Here we will learn about commonly used string functions with its usage.

Getting the Length

The strlen() function can be used to get the length of a string.

$str = 'Hyvor Developer';
echo strlen($str); // outputs 15

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Number of Words

The str_word_count() function returns the number of words in a string.

$str = 'This is a string with seven words';
echo str_word_count($str);

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Changing The Case

The strtolower() and strtoupper() are used to make a string lowercase and uppercase respectively.

$str = 'Hyvor Developer';

echo strtolower($str); // hyvor developer
echo '<br>';
echo strtoupper($str); // HYVOR DEVELOPER

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Removing Unnecessary Whitespace

The trim() function removes unnecessary whitespace from the beginning and the end of a string.

$str = '  Hyvor Developer    ';
echo strlen($str) . '<br>'; // length is 21

$str = trim($str); // remove whitespace
echo strlen($str); // now, length is 15

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Note: The trim() function is commonly used with PHP Forms.


The strrev() function is used to reverse a string.

$str = 'Hyvor Developer';
echo strrev($str);

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The strpos() function returns the position of the first occurrence of a substring in a string.

$str = 'Hello World';
echo strpos($str, 'World'); // will output 6

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Tip: In PHP, index of strings starts from 0. Therefore, the strpos() function returns 6 instead of 7 in the above example.

Replacing Text within a String

The str_replace() function replaces a text within a string.

In this example, "Morning" in "Good Morning" will be changed to "Evening". The final result will be "Good Evening".

$str = 'Good Morning';
echo str_replace('Morning', 'Evening', $str);

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Repeating a String

The str_repeat() function is used to repeat a string number of times.

echo str_repeat('*', 20);

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Formatted Strings

The sprintf() function is used to get formatted (or dynamic) strings.

$amount = 5.44;
echo sprintf('The amount is $%F <br>', $amount);
$myName = 'Hyvor';
$age = 10;
echo sprintf("My name is %s. I'm %d years old", $myName, $age);

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% is used as a placeholder. And, you can have any number of arguemnts.

  • %d - Decimal
  • %s - String
  • %f - Float
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