PHP：将速记十六进制颜色转换为常规

Question

I'm trying to make a function that will take short hand hex color to the long hex color.

For example if someone submits "f60" it will convert to "ff6600". I understand I need to repeat each number as itself, but what is the most efficient way to do this?

Thank you.

Answer 1

This should work. However, you'll want to make sure the strings aren't prepended with a # due to the exact strlen comparison.

// Done backwards to avoid destructive overwriting
// Example: f60 -> ff6600
if (strlen($color) == 3) {
    $color[5] = $color[2]; // f60##0
    $color[4] = $color[2]; // f60#00
    $color[3] = $color[1]; // f60600
    $color[2] = $color[1]; // f66600
    $color[1] = $color[0]; // ff6600
}

Answer 2

$fullColor = $color[0].$color[0].$color[1].$color[1].$color[2].$color[2];

您可以将字符串的字符作为数组访问。

Answer 3

this question cannot miss the good old regexes :D

 $color = preg_replace('/#([\da-f])([\da-f])([\da-f])/i', '#\1\1\2\2\3\3', $color);

not the best solution though …

Answer 4

Not the most efficient, but an alternative with these you can duplicate every kind of string with every length not only 3 as Hex colors

   <?php
     $double='';
     for($i=0;$i<strlen($str);$i++){
            $double.=$str[$i].$str[$i];
     }
   ?>

or

<?php
 $str="FCD";
 $split=str_split($str);
 $str='';
 foreach($split as $char) $str.=$char.$char;
 echo $str;
?>

You could also use regex or other...