String to Array

[mister5317]

I have a string that I need converted to a nested array.  See code below:

// Input string
$string = 'Paths.Images.Icons';

/*
Need the following back:
Array
(
    [Paths] => Array
    (
        [images] => Array
        (
            [icons] => Array
            (
            )
        )
    )
)

*/

 

I need a function that will parse the input string and generate a nested array based on the periods in the input string.

 

Can someone help me create a function to do this?

 

Thanks!

 

 

[flyhoney]

Try this:

 

<?php
str_to_nested_array($array, 'Paths.Images.Icons');

function str_to_nested_array(&$array, $string) {
function foo(&$array, $parts) {
	if (is_array($parts) and !empty($parts)) {
		$index = array_shift($parts);
		$array[$index] = array();
		foo($array[$index] , $parts);
	}
}
foo($array, explode('.', $string));
}

print_r($array);
?>

[mister5317]

That is perfect!

 

Can you please explain the code a little bit?  I have never used a function within a function like this...

 

Thanks again!

[mister5317]

Sorry, one more question, is it possible to call the function with the only argument being the input string?

 

<?php
$array = str_to_nested_array('Paths.Images.Icons');
?>

[flyhoney]

Yeah its kind of complicated.

 

Here is a breakdown with comments:

 

<?php
// $array is passed by reference so that any changes made to $array
// inside this function will apply to $array outside of the function
function str_to_nested_array(&$array, $string) {

   // This is a recursive function, that means it is a function that calls itsself.
   // Again, $array is passed by reference so any changes made to it within foo()
   // will apply to $array  outside of foo().
   function foo(&$array, $parts) 
   {
      // Make sure that the $parts array is not empty
      if (is_array($parts) and !empty($parts)) 
      {
         // remove the first element from the $parts array
         $index = array_shift($parts);

         // create an array using $index
         $array[$index] = array();

         // call foo again, but now $array is the nested array we just created
         foo($array[$index] , $parts);
      }
   }

   // start the process of creating the nested array
   foo($array, explode('.', $string));
}
?>

[flyhoney]

Yeah

 

<?php
$array = str_to_nested_array('Paths.Images.Icons');
print_r($array);

function str_to_nested_array($string) 
{
function foo(&$array, $parts) 
{
	if (is_array($parts) and !empty($parts))
	{
		$index = array_shift($parts);
		$array[$index] = array();
		foo($array[$index] , $parts);
	}
}
$array = array();
foo($array, explode('.', $string));
return $array;
}
?>

[.josh]

I like living dangerously....

 

$string = 'Paths.Images.Icons.X';
$nodes = explode('.',$string);
$c = count($nodes) + 1;
$eval = '$structure = array(\'' . implode("' => array('", $nodes) . "' => array(" . str_repeat(")", $c) . ";";
eval($eval);

echo "<pre>";
print_r($structure);

[flyhoney]

I like living dangerously....

 

$string = 'Paths.Images.Icons.X';
$nodes = explode('.',$string);
$c = count($nodes) + 1;
$eval = '$structure = array(\'' . implode("' => array('", $nodes) . "' => array(" . str_repeat(")", $c) . ";";
eval($eval);

echo "<pre>";
print_r($structure);

 

gross.

[.josh]

Don't be jealous

[printf]

It's no worse than using STACK overflow dangerous recursion! Me likes eval();

[flyhoney]

I may be jealous, but you should be ashamed.

[flyhoney]

Blarg, you're faster.

 

flyhoney: 3.6954879760742E-5
CV:       3.0040740966797E-5

 

but still terrible

[corbin]

flyhoney, are you sure you should be declaring that function in a function?  What if he calls the parent function twice?

 

 

 

 

Anyway, wouldn't:

 

$e = explode('.', $str);
$a = array();
$parent =& $a;
foreach($e as $v) {
    $parent[$v] = array();
    $parent =& $parent[$v];
}

 

work?

[flyhoney]

Wow, I had no clue that it would throw an error.  Good game to me.

 

Yeah your solution is nice. I wasn't even aware of the =& operator!

 

**EDIT**

 

I am an idiot. 

[corbin]

If we're gonna compare speeds:

 

 

corbin: 1.2086191177368

cv: 3.4495089054108

flyhoney: 3.5196778774261

 

 

 

Hehehhe ;p.

 

 

Yours could be further optimized though.  Over 100,000 calls that I had it make, an extra function call can become expensive.  Hrmmm....

 

 

 

And yeah, defining a function anywhere twice will throw a fatal error.

[flyhoney]

And yeah, defining a function anywhere twice will throw a fatal error.

 

I guess I assumed that since it was within the scope of the other function it would live and die as the parent function was called.  Not the case!

 

So, poor fella that start this thread:

 

<?php
function str_to_nested_array($string) 
{
$e = explode('.', $string);
$a = array();
$parent =& $a;
foreach($e as $v) 
{
	$parent[$v] = array();
	$parent =& $parent[$v];
}
return $a;
}

$array = str_to_nested_array('Paths.Images.Icons.X');
print_r($array);
?>

[.josh]

Okay I cleaned mine up a bit. How does this compare?

 

$string = "Paths.Images.Icons";
$nodes = explode('.',$string);
$eval = '$structure[' . implode('][', $nodes) . '] = array();';
eval($eval);

[.josh]

Okay corbin, you said 100k runs, right? Looks like my cleaned up version averages at 1.95s.  Lot faster than before, but yours still wins :\

[flyhoney]

corbin: 2.1934509277344E-5
CV:     2.598762512207E-5

 

I also had to edit your code:

$eval = '$structure[\'' . implode('\'][\'', $nodes) . '\'] = array();';

 

to not throw errors

[.josh]

Yeah I knew that would happen. Final code:

 

function strToNestedArray($string) {
   return eval('$structure[\'' . implode('\'][\'', explode('.',$string)) . '\'] = array();');
}

 

corbin's is a little faster but come on, like 0.4s over 100k times is not even worth mentioning, and let's face it, mine is sexier.

 

[corbin]

flyhoney, it looks like you're testing things with 1 iteration.... I usually do at least a couple thousand since it can be misleading to only do it once.

 

 

 

 

Anyway, CV, I don't know what beastly hardware you're running, but I get this:

 

corbin: 1.226273059845

cv: 2.9218299388885

 

With your new function.  Perhaps you're using a shorter string and it's not hardware.  Eitherway, try BM'ing both of ours on your machine.

 

 

Edit:  CV, I'm quite sure your newest function will return NULL.

 

Regardless:

 

corbin: 1.215723991394

cv: 2.9700248241425

 

And yes, yours is much sexier.

[.josh]

hmmm...apparently it's faster for me to separate the calls.... you did kick my ass in the speed test when I reduced it:

 

<?php
// corbin's function
function str_to_nested_array($string) 
{
   $e = explode('.', $string);
   $a = array();
   $parent =& $a;
   foreach($e as $v) 
   {
      $parent[$v] = array();
      $parent =& $parent[$v];
   }
   return $a;
}

// crayon's function
function strToNestedArray($string) {
   eval('$structure[\'' . implode('\'][\'', explode('.',$string)) . '\'] = array();');
   return $structure;
}

$str = "path.to.something";

echo "100k call * 10 benchmarking: <br/><br/>";
echo "Crayon Test<br/>";
for ($y = 0; $y < 10; $y++) {
$start = microtime(true);
for ($x = 0; $x < 100000; $x++) {
   $structure = strToNestedArray($str);
}
$time = microtime(true) - $start;
echo $time . "<br/>";
}

echo "<br/>Corbin Test<br/>";
for ($y = 0; $y < 10; $y++) {
$start = microtime(true);
for ($x = 0; $x < 100000; $x++) {
   $array = str_to_nested_array($str);
}
$time = microtime(true) - $start;
echo $time . "<br/>";
}

 

100k call * 10 benchmarking:

 

Crayon Test

1.42691397667

1.41678309441

1.42388701439

1.42499303818

1.43931484222

1.41837310791

1.42116189003

1.4214861393

1.41087889671

1.4306139946

 

Corbin Test

0.469434022903

0.469136953354

0.466317176819

0.471101999283

0.463952064514

0.470424890518

0.477626800537

0.474759101868

0.469851016998

0.471065044403

[corbin]

I'm jealous of your processor (well, I used a decent length string; perhaps you used very short) .

 

 

But like you said, in the real world, this function would probably be used 1-100 times on a page, meaning the time difference would be so small it wouldn't matter.

 

 

0.000014 - .0000047 = 0.0000093 per call.

 

 

>.<

 

 

And your solution is definitely sexier ;p.  To be honest though, I would think your solution would be slower than it is.  Eval and string functions....  Weird.

 

 

Edit:  Just realized why the string and eval don't matter much (especially the string functions)....  Our data sets were small.

[.josh]

10 'layers'

String Used:

something.something.something.something.something.something.something.something.something.something

100k call * 10 benchmarking:

 

Crayon Test

2.87430691719

2.93059802055

2.80796098709

2.83842396736

2.80413508415

2.80233502388

2.81222605705

2.80466985703

2.81069684029

2.79373407364

 

Corbin Test

1.18330597878

1.18677306175

1.21304512024

1.18618011475

1.18019294739

1.19304704666

1.18475985527

1.19489097595

1.20416808128

1.19843006134

 

100 'layers'

String Used:

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something.

something.something.something.something.something.something.something.something.something.something

100k call * 10 benchmarking:

 

Crayon Test

20.3001179695

17.857063055

17.776542902

17.6992988586

17.8040530682

17.7113671303

17.9984920025

18.9144699574

17.6936171055

17.8100349903

 

Corbin Test

9.2130241394

9.54194021225

9.23869395256

9.26948809624

9.1253631115

9.40434908867

9.11741280556

9.14707803726

9.14307904243

9.22559309006

[.josh]

btw this is my host's server info: http://74.54.71.140/~netadmin/