How to replace text in PHP?

Use str_replace($search, $replace, $subject). Example: str_replace('old', 'new', $text) replaces all 'old' with 'new'.

Is str_replace() case sensitive?

Yes, str_replace() is case-sensitive. Use str_ireplace() for case-insensitive replacement.

Can str_replace() do multiple replacements?

Yes, pass arrays: str_replace(['a','b'], ['x','y'], $text) replaces 'a' with 'x' and 'b' with 'y'.

PHP str_replace() Function

String Function PHP 4+

The str_replace() function replaces all occurrences of a search string (or array of strings) with a replacement string (or array).

Syntax

str_replace(
    array|string $search,
    array|string $replace,
    string|array $subject,
    int &$count = null
): string|array

Parameters

Parameter	Type	Description
`$search`	string\|array	The value(s) to search for
`$replace`	string\|array	The replacement value(s)
`$subject`	string\|array	The string or array to search in
`$count`	int	Optional. Number of replacements performed

Return Value

Returns a string or array with all occurrences of search replaced with replace.

Try It Online

<?php
// str_replace() - Replace all occurrences of search with replacement
// One of the most used string functions in PHP

// Example 1: Simple replacement
$text = "Hello World!";
echo "Original: $text\n";
echo "Replace 'World' with 'PHP': " . str_replace("World", "PHP", $text) . "\n\n";

// Example 2: Replace ALL occurrences
$repeated = "PHP is cool. PHP is fast. PHP is popular.";
echo "Original: $repeated\n";
echo "Replace all 'PHP': " . str_replace("PHP", "Python", $repeated) . "\n\n";

// Example 3: Multiple search/replace pairs
$template = "Dear {NAME}, your order #{ORDER_ID} is {STATUS}.";
echo "Template: $template\n";

$result = str_replace(
    ["{NAME}", "{ORDER_ID}", "{STATUS}"],
    ["John", "12345", "shipped"],
    $template
);
echo "Filled: $result\n\n";

// Example 4: Count replacements
$html = "<p>First</p> <p>Second</p> <p>Third</p>";
$count = 0;
$result = str_replace("<p>", "<div>", $html, $count);
$result = str_replace("</p>", "</div>", $result);
echo "HTML: $html\n";
echo "Converted: $result\n";
echo "Replacements made: $count\n\n";

// Example 5: Create URL slug
$title = "Hello World! This is a Test.";
$slug = str_replace(" ", "-", strtolower($title));
$slug = str_replace(["!", "."], "", $slug);
echo "Title: $title\n";
echo "Slug: $slug\n";

Output

Click Run to execute your code

More Examples

Simple Replace

<?php
$text = "Hello World";
$result = str_replace("World", "PHP", $text);
echo $result;  // "Hello PHP"
?>

Multiple Replacements

<?php
$text = "I like apples and apples are healthy";
$result = str_replace(
    ["apples", "healthy"],
    ["oranges", "delicious"],
    $text
);
echo $result;
// "I like oranges and oranges are delicious"
?>

Count Replacements

<?php
$text = "PHP is great. PHP is powerful.";
$count = 0;
$result = str_replace("PHP", "Python", $text, $count);
echo "Made $count replacements\n";  // Made 2 replacements
echo $result;
?>

Tip: For case-insensitive replacements, use str_ireplace() instead.

Common Use Cases

Template variable replacement
Sanitizing user input
URL slug generation
Text formatting

Related Functions

str_ireplace() - Case-insensitive version
substr() - Extract part of a string
strpos() - Find position of substring
preg_replace() - Regex-based replacement

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