Question

How to compare two strings alphabetically (lexicographically) in PHP

Answer 1

$s1 = "php";
$s2 = "javascript";

if (strcmp($s1, $s2) !== 0) 
    echo "$s1 is not equal to $s2";

 
/*
run: 

php is not equal to javascript

*/

 

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Answer 2

$s1 = "php";
$s2 = "PHP";

if (strcmp($s1, $s2) !== 0) 
    echo "$s1 is not equal to $s2";

 
/*
run: 

php is not equal to PHP

*/

 

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Answer 3

$s1 = "php";
$s2 = "PHP";

if (strcasecmp($s1, $s2) !== 0) // ignores case
    echo "$s1 is not equal to $s2";
else    
    echo "$s1 is equal to $s2";

 
/*
run: 

php is equal to PHP

*/

 

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Answer 4

// strcmp(string $string1, string $string2): int
// Returns:
// -1 (< 0) if string1 is less than string2
// 1 (> 1) if string1 is greater than string2
// 0 if they are equal
 
echo strcmp("aa", "ab") . "\n"; // <
echo strcmp("a", "b") . "\n"; // <
echo strcmp("a", "c") . "\n"; // <

echo strcmp("aa", "aa") . "\n"; // ==

echo strcmp("ba", "aa") . "\n"; // >
echo strcmp("ca", "aa") . "\n"; // >
echo strcmp("ab", "aa") . "\n"; // >

 
  
/*
run: 
 
-256
-1
-2
0
1
2
256

 
*/

 

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