Implode() FR and Patch View as Markdown

Hello There,

I would like to propose a third argument to implode(), named
skip_empty, that will cause empty elements to be ignored when
generating the implode string. By empty I mean everything that
converts to an empty string such as '', false, null, etc.

For example:

<?php
$a = array(1,'',2,null,3,0,4,true,5,false,false);
echo implode(',', $a); // old behavior
echo "\n";
echo implode(',', $a, true); // new feature
echo "\n";
echo $foo;
echo "\n";
?>

Will output:

1,,2,,3,0,4,1,5,,
1,2,3,0,4,1,5

Obviously the new parameter defaults to 'false' for backwards compatibility.

The patch file is attached for evaluation, review, feedback etc.
Please keep in mind that this is my first time playing with PHP source
so expect flaws on my code.

I did a few simple tests (using time, if someone has a non buggy
valgrind for OS X please let me know) against 5.3 CVS (named php53 in
examples) and my patched version (named php+ in examples). The PHP
scripts are right below the tests. Looking at the results I would say
there is almost no performance loss.

Before I place a feature request at PHP.net I would love to hear some
feedback here, or even a yes/no for this feature.

Best Regards,
Igor Feghali.

=== TEST 1 ===
$ time ./php53 /tmp/more_small.php
real 0m0.257s
user 0m0.223s
sys 0m0.032s

$ time ./php53 /tmp/more_small.php
real 0m0.258s
user 0m0.224s
sys 0m0.032s

$ time ./php53 /tmp/more_small.php
real 0m0.260s
user 0m0.225s
sys 0m0.032s

$ time ./php+ /tmp/more_small.php
real 0m0.261s
user 0m0.226s
sys 0m0.033s

$ time ./php+ /tmp/more_small.php
real 0m0.258s
user 0m0.224s
sys 0m0.032s

$ time ./php+ /tmp/more_small.php
real 0m0.260s
user 0m0.225s
sys 0m0.033s

=== TEST 2 ===
$ time ./php53 /tmp/less_big.php
real 0m0.328s
user 0m0.205s
sys 0m0.120s

$ time ./php53 /tmp/less_big.php
real 0m0.328s
user 0m0.206s
sys 0m0.120s

$ time ./php53 /tmp/less_big.php
real 0m0.326s
user 0m0.205s
sys 0m0.119s

$ time ./php+ /tmp/less_big.php
real 0m0.330s
user 0m0.206s
sys 0m0.122s

$ time ./php+ /tmp/less_big.php
real 0m0.330s
user 0m0.206s
sys 0m0.121s

$ time ./php+ /tmp/less_big.php
real 0m0.333s
user 0m0.207s
sys 0m0.124s

=== TEST 3 ===
$ time ./php+ /tmp/lots_null.php
real 0m0.263s
user 0m0.229s
sys 0m0.032s

$ time ./php+ /tmp/lots_null.php
real 0m0.261s
user 0m0.227s
sys 0m0.032s

$ time ./php+ /tmp/lots_null.php
real 0m0.260s
user 0m0.226s
sys 0m0.032s

$ time ./php+ /tmp/no_null.php
real 0m0.259s
user 0m0.226s
sys 0m0.032s

$ time ./php+ /tmp/no_null.php
real 0m0.257s
user 0m0.223s
sys 0m0.031s

$ time ./php+ /tmp/no_null.php
real 0m0.264s
user 0m0.229s
sys 0m0.032s

=== SCRIPTS ===
less_big.php
<?php

$str = str_repeat(str_repeat('foo', 1000).',', 11345);
$arr = explode(',', $str);

$out = implode(',', $arr);

lots_null.php
<?php

$str = str_repeat('foo,,', 99999);
$arr = explode(',', $str);

$out = implode(',', $arr);

more_small.php
<?php

$str = str_repeat('foo,bar,', 99999);
$arr = explode(',', $str);

$out = implode(',', $arr);

no_null.php
<?php

$str = str_repeat('foo,,', 99999);
$arr = explode(',', $str);

$out = implode(',', $arr, true);