Hi,
The function Robert proposes only works for going one key deep.
That means one would have to specify getd($arr['sublevel'],$subkey),
which would then create the key 'sublevel'.
(That is assuming one has access to the parent keys)
I have addressed this in the following function:
function arr_getd(&$space,$path,$default=""){
if (is_array($space) ):
if (array_key_exists($path,$space) ):
return $space[$path];
endif;
if($path{0}=="$"):
$path=substr($path,1);
endif;
if(strpos($path,"]")>0):
$tmp_pos = strpos($path,"[");
if ($tmp_pos>0):
// rep arr x[.]
$path = '["'.substr($path,0,$tmp_pos).'"]'.substr($path,$tmp_pos);
endif;
return eval("return (isset(\$space$path))?\$space$path:\$default;");
endif;
endif;
return $default;
}
Now, I can pass in a string representation like this:
$val = arr_getd($arr,"['sublevel']['$subkey']","default");
This allows me to control at what point the reference autovivifies the
passed-in array space.
Unfortunately, this approach requires the use of eval in order to
access the isset() function. Coupled with the logic and string
functions, it takes a significant performance hit.
Since I use this inside loops, I would very much appreciate a
language-level implementation similar to isset(), which doesn't require
that a variable be passed in as a string representation.
Is such a thing is acceptable to the majority?
Guy N. Hurst
Robert Cummings wrote:
> Why not augment the userland function to the following:
>
> function getd( &$sourceArray, $key, $default=null )
> {
> if( isset( $sourceArray[$key] ) )
> {
> return $sourceArray[$key];
> }
>
> return $default;
> }
>
> Cheers,
> Rob.
>
>
> On Mon, 2003-08-18 at 17:03, Griggs Domler wrote:
>
>>It's rare to find functionality that cannot be effectively implemented
>>in userland PHP code, but this appears to be one of them.
>>
>>The issue here is the capability to check if an array index (or
>>variable) is set, if so, return its value, or return a passed in default
>>value. This can be accomplished using if statements or the ternary
>>operator, but they quickly become tiresome for so routine a task.
>>Especially when dealing with nested associative arrays, for example:
>>
>>$myVar =
>>(isset($_SESSION['application']['section']['page']['title']))?$_SESSION[
>>'application']['section']['page']['title']:"Default Title";
>>
>>Wouldn't this be better:
>>
>>$myVar =
>>getd($_SESSION['application']['section']['page']['title'],"Default
>>Title");
>>
>>At first glance defining a function that will accomplish this appears
>>easy:
>>
>>function getd($var,$default='')
>>{
>> if(isset($var))
>> return $var;
>> else
>> return $default;
>>}
>>
>>$myVar = getd($arr['noindex']);
>>
>>But this is not notice level compliant, producing an error if the index
>>doesn't already exist.
>>
>>Re-writing the function to pass by reference seems to fix this at first
>>glance:
>>
>>function getd(&$var,$default='')
>>{
>> . . .
>>}
>>
>>$myVar = getd($arr['noindex']);
>>
>>
>>It no longer gives a notice. But the call mentioned above will now
>>create the index mentioned, setting its value to null, which, while not
>>necessarily wrong, still means that a foreach iteration or array_keys()
>>call will show that the key now exists. (though isset() will not.)
>>
>>Since writing a userland function to accomplish this seems impossible
>>while maintaining notice-level compliance, could this be accomplished at
>>the language level? Perhaps by adding a statement similar to isset? It
>>would seem a very helpful addition to PHP and would not need to affect
>>other language constructs.
>
--
Guy Hurst
Senior Developer
Web Teks, Inc.
http://www.webteks.com
Phone: 757.578.4923
Toll free: 877.Web.Teks
Fax: 757.578.4996
