In this PHP tutorial, you shall learn how to compare given two strings using strcmp() function, with example programs.

PHP Compare Strings

To compare strings in PHP, you can use strcmp() function. strcmp() can find if a string is smaller, equal to, or larger than the other string.

The syntax of strcmp() function to compare $string1 and $string2 is

result = strcmp($string1, $string2)

strcmp() compares strings lexicographically.

  • If $string1 precedes $string2 when arranged lexicographically in ascending order, $string1 is said to be smaller than $string2. In this case, strcmp($string1, $string2) returns negative value.
  • If $string1 comes after $string2 when arranged lexicographically in ascending order, $string1 is said to be larger than $string2. In this case, strcmp($string1, $string2) returns positive value.
  • If $string1 equals $string2, then strcmp($string1, $string2) returns 0.

Examples

1 Compare strings, given string1 is less than string2

In this example, we will take two strings: “apple”, “banana”. First string comes prior to second string when arranged in ascending order lexicographically. So, when we pass these two strings as arguments to strcmp(), it should return a negative value.

PHP Program

<?php
$string_1 = "apple";
$string_2 = "banana";
$result = strcmp($string_1, $string_2);
echo $result;
?>

Output

2 Compare strings, given string1 is equal to string2

In this example, we will take two strings: “apple”, “apple”. Both the strings are equal. So, when we pass these two strings as arguments to strcmp(), it should return a value of zero.

PHP Program

<?php
$string_1 = "apple";
$string_2 = "apple";
$result = strcmp($string_1, $string_2);
echo $result;
?>

Output

3 Compare strings, given string1 is greater than string2

In this example, we will take two strings: “orange”, “apple”. First string comes after the second string when arranged in ascending order lexicographically. So, when we pass these two strings as arguments to strcmp(), it should return a positive value.

PHP Program

<?php
$string_1 = "orange";
$string_2 = "apple";
$result = strcmp($string_1, $string_2);
echo $result;
?>

Output

Conclusion

In this PHP Tutorial, we learned how to compare two strings in PHP using strcmp() built-in function.