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gmp_hamdist

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

gmp_hamdistHamming distance

Description

gmp_hamdist(GMP|int|string $num1, GMP|int|string $num2): int

Returns the hamming distance between num1 and num2. Both operands should be non-negative.

Parameters

num1

A GMP object, an int or a numeric string.

It should be positive.

num2

A GMP object, an int or a numeric string.

It should be positive.

Return Values

The hamming distance between num1 and num2, as an int.

Examples

Example #1 gmp_hamdist() example

<?php
$ham1
= gmp_init("1001010011", 2);
$ham2 = gmp_init("1011111100", 2);
echo
gmp_hamdist($ham1, $ham2) . "\n";

/* hamdist is equivalent to: */
echo gmp_popcount(gmp_xor($ham1, $ham2)) . "\n";
?>

The above example will output:

6
6

See Also

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User Contributed Notes 2 notes

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4
Bas Vijfwinkel
6 years ago
For those without gmp support :

$hamming_distance = count(array_diff_assoc(str_split($string1), str_split($string2)));

And if you are not sure if your strings have equal length :

$hamming_distance = count(array_diff_assoc(str_split(str_pad($string1,strlen($string2)-strlen($string1),' ')), str_split(str_pad($string2,strlen($string1)-strlen($string2),' '))));
up
-1
grabzila at gmail dot com
3 years ago
<?php
$hamdist
= gmp_hamdist(-100, -10); // 4
$hamdist = gmp_hamdist(100, 10); // 5
?>

The function works great with negative numbers.
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