How to Compare Strings In PHP ? See Example

String comparison is a common task in PHP when checking equality, sorting values, validating input, or performing case-sensitive/insensitive checks. PHP provides several operators and functions to compare strings effectively.

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1. Comparing Strings Using Operators

a) Equal (==)

Checks if two strings have the same value, case-sensitive.

$str1 = "Hello";
$str2 = "Hello";

if ($str1 == $str2) {
    echo "Strings are equal";
}

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b) Identical (===)

Checks value and type.

$str1 = "123";
$str2 = 123;

if ($str1 === $str2) {
    echo "Same";
} else {
    echo "Not same"; // Output
}

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c) Not Equal (!= or <>)

if ("apple" != "banana") {
    echo "Different strings";
}

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2. Case-Insensitive Comparison

Use strcasecmp().

if (strcasecmp("Hello", "hello") == 0) {
    echo "Same (case-insensitive)";
}

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3. Natural Order Comparison (strnatcmp)

Useful when comparing strings with numbers.

echo strnatcmp("file2", "file10"); // file2 < file10

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4. Comparing Portions of Strings

Use strncmp() to compare first n characters.

echo strncmp("HelloWorld", "HelloPHP", 5); // 0 means equal

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5. Using strcmp()

Standard binary-safe string comparison.

$result = strcmp("abc", "abd");

if ($result < 0) echo "abc < abd";
if ($result > 0) echo "abc > abd";
if ($result == 0) echo "Equal";

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6. Comparing Strings with Spaces & Trimming

$str1 = " Hello ";
$str2 = "Hello";

if (trim($str1) === trim($str2)) {
    echo "Equal after trimming";
}

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7. Safe Comparison for User Input

Always sanitize before comparing.

$user = strtolower(trim($_POST['username']));
$actual = "admin";

if ($user === $actual) {
    echo "Access granted";
}

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Conclusion

String comparison in PHP can be simple or advanced based on your needs—using operators for basic checks and functions like strcmp() and strcasecmp() for more control.

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Citations

🔗 View other articles about PHP:
http://savanka.com/category/learn/php/

🔗 External PHP Documentation:
https://www.php.net/manual/en/