strcoll() Function for Locale-Aware String Comparison

The PHP strcoll() function is used to compare two strings based on the current locale settings. It performs a locale-aware comparison, which makes it more suitable for handling strings in different languages and regional settings compared to binary comparison functions like strcmp().

Syntax

int strcoll ( string $string1 , string $string2 )

$string1: The first string to be compared.
$string2: The second string to be compared.
Return Value: This function returns:

Less than 0 if $string1 is less than $string2.
Greater than 0 if $string1 is greater than $string2.
0 if $string1 is equal to $string2.

Basic Example of strcoll()

In the following example, we compare two strings using the strcoll() function.

$str1 = "apple";
$str2 = "banana";
echo strcoll($str1, $str2); // Output will be less than 0 because "apple" is less than "banana"

Output:

-1

Example with Equal Strings

Here, we compare two identical strings, and the function returns 0.

$str1 = "apple";
$str2 = "apple";
echo strcoll($str1, $str2); // Output will be 0 because both strings are the same

Output:

Locale-Aware Example

To see how strcoll() behaves differently in various locales, let's set the locale to a specific language.

setlocale(LC_COLLATE, 'en_US');  // Set locale to US English
$str1 = "apple";
$str2 = "Apple";
echo strcoll($str1, $str2); // Output will be greater than 0 because "apple" > "Apple" in US locale

setlocale(LC_COLLATE, 'fr_FR');  // Set locale to French
echo strcoll($str1, $str2); // Output might change depending on French locale rules

Output:

1
1

Comparing Numeric Strings

When comparing numeric strings, strcoll() treats them like strings based on the current locale, not as numbers.

$str1 = "123";
$str2 = "456";
echo strcoll($str1, $str2); // Output will be less than 0 because "123" is less than "456"

Output:

-1

Case-Sensitive Comparison

Unlike strcasecmp(), the strcoll() function performs a case-sensitive comparison based on locale settings.

$str1 = "Hello";
$str2 = "hello";
echo strcoll($str1, $str2); // Output depends on the locale, but typically it's case-sensitive

Output:

-1

Conclusion

The PHP strcoll() function is useful when you need locale-aware string comparison. It’s more appropriate than binary comparison functions when dealing with strings in different languages or regional formats. By using the locale settings, it ensures that comparisons are done according to cultural and linguistic rules, making it highly flexible for international applications.
String Functions Next: strrev() - Reversing a String chunk_split(): Split a string into smaller chunks

Subhendu Mohapatra

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strcoll(): locale-based string comparison

Syntax

Basic Example of strcoll()

Example with Equal Strings

Locale-Aware Example

Comparing Numeric Strings

Case-Sensitive Comparison

Conclusion

Subhendu Mohapatra