Help converting an array into comma separated values

[TheBrandon]

Hello all,

 

I'm trying to get better at manipulating arrays and I'm stumped on this one.

 

What would be the most efficient way of converting an array such as this:

 

Array ( [3] => 3 [9] => 1 [15] => 9 )

 

Into this:

 

3,3,3,9,15,15,15,15,15,15,15,15,15

 

 

[Pikachu2000]

implode

[scootstah]

It's probably not the most efficient way, but this works:

$input = array('3' => 3, '9' => 1, '15' => 9);

$str = '';

foreach($input as $key => $val)
{
for($i = 0; $i < $val; $i++)
{
	$str .= $key . ',';
}
}

$str = rtrim($str, ',');

 

EDIT: This is better:

$input = array('3' => 3, '9' => 1, '15' => 9);

$str = '';

foreach($input as $key => $val)
{
$str .= str_repeat($key . ',', $val);
}

$str = rtrim($str, ',');

[TheBrandon]

implode

 

implode alone is capable of that? Could you show me an example of how to achieve this using implode? I've been trying to do it with a foreach loop.

[TheBrandon]

It's probably not the most efficient way, but this works:

$input = array('3' => 3, '9' => 1, '15' => 9);

$str = '';

foreach($input as $key => $val)
{
for($i = 0; $i < $val; $i++)
{
	$str .= $key . ',';
}
}

$str = rtrim($str, ',');

 

EDIT: This is better:

$input = array('3' => 3, '9' => 1, '15' => 9);

$str = '';

foreach($input as $key => $val)
{
$str .= str_repeat($key . ',', $val);
}

$str = rtrim($str, ',');

 

Oh okay, the first one is similar to what I was doing. I'll look into str_repeat, thanks a lot! =)

[xyph]

It's hard to improve much on scootstah's solution. This is an alternate, using str_repeat. It could be faster, but if it is, you'd have to run it a million times before it'd make a noticeable difference

 

<?php

$array = array(3=>3,9=>1,15=>9);

$out = '';
foreach( $array as $val => $mult )
$out .= str_repeat("$val,", $mult);
$out = substr($out,0,-1);

echo $out;

?>

 

[edit] Ninja'd by scoot's edit [/edit]

[Pikachu2000]

implode

 

implode alone is capable of that? Could you show me an example of how to achieve this using implode? I've been trying to do it with a foreach loop.

 

Oh, I guess I should have examined the values more closely when I saw there were more values than array elements. No, implode() will not do that on its own.