On 14 April 2011 09:59, Eloy Bote Falcon <eloyb...@gmail.com> wrote:
> What is the purpose of that generateHash function? It doesn't work in the
> isset check.
>
> Anyway, you can do a simple $a = array('foo'); isset($a[$x][$y][$z]) without
> notices at all unless any of $x $y or $z are not defined, you don't need to
> check the indexes one by one.
>
> 2011/4/14 Ole Markus With <olemar...@olemarkus.org>
>
>> On Thu, 14 Apr 2011 02:24:56 +0200, Ben Schmidt <
>> mail_ben_schm...@yahoo.com.au> wrote:
>>
>> I think these shortcuts could be really useful for array elements, but
>>>> for other variables I am really sceptical and I think they would do
>>>> more harm than good. Generally I do not really see any reason why a
>>>> variable should not be 'instanciated' before use.
>>>>
>>>> So
>>>> +1 if this shortcut is implemented to only work for array elements.
>>>> -1 for any other variable type.
>>>>
>>>
>>> There are two issues here.
>>>
>>> 1. Suppression of notice. I agree, it is best done only for array
>>> keys. It's not hard to initialise a variable with $var=null at the
>>> beginning of a code block to avoid such a notice, and that is the
>>> appropriate way to do it for variables.
>>>
>>> 2. Offering a shortcut for the common idiom isset($x) ? $x : $y in
>>> line with the DRY design principle. A notice would never be emitted
>>> here in any case. The problem is that this idiom is still in wide use
>>> despite the shortcut ternary operator already provided, because an
>>> isset() check is different to a boolean cast.
>>>
>>> Some thoughts:
>>>
>>> - The actual intent of 2. is probably $x!==null ? $x : $y i.e. it's
>>> not about suppressing notices at all, but about offering a default
>>> value, and the idiom quite probably only uses isset() because it
>>> predated null in the language.
>>>
>>>
>> I have never felt the need for a shortcut in these cases. It would be
>> interesting to see some code where this would be practical.
>>
>>
>> - If we view 2. in this way, the two problems are independent, and it
>>> seems to me it would be best to solve them independently, rather
>>> than with a single operator.
>>>
>>> So, I suggest:
>>>
>>> 1. An array lookup mechanism that suppresses the notice for undefined
>>> keys. It would work the same as regular array index lookups except
>>> that the notice for undefined keys (and only for undefined keys)
>>> would not be generated (it would not just be hidden, but would never
>>> be even generated).
>>>
>>
>> This is what I feel PHP is missing. Particularly when it comes to
>> multi-dimensional arrays. Because this feature is missing I tend to do
>> something like
>>
>> function generateHash($x, $y, $z)
>> {
>> return "$x::$y::$z";
>> }
>>
>> if (isset($a[generateHash($x, $y, $z)]) {
>> ...
>> }
>>
>> instead of
>>
>> if (isset($a[$x]) && isset($a[$x][$y]) && isset($a[$x][$y][$z])) {
>> ...
>>
>> }
>>
>> Arguing about syntax is then a second step. However, my views on this
>>> are:
>>>
>>>
>> I think it best to avoid discussing the actual syntax before agreeing on
>> what we really need.
>>
>> --
>> Ole Markus With
>> Systems Architect - Sportradar AS
>> Developer - Gentoo Linux
>>
>>
>> --
>> PHP Internals - PHP Runtime Development Mailing List
>> To unsubscribe, visit: http://www.php.net/unsub.php
>>
>>
>
http://news.php.net/php.internals/51877
array_key_exists($key, $array) for arrays
array_key_exists($varname, get_defined_vars()) for locally scoped variables.
No need to use @.
isset() and empty() will not differentiate between an undefined
variable or index and a variable or an array element which is assigned
null.
The E_NOTICE only ever gets fired for the undefined variable/key ...
Notice: Undefined variable
Notice: Undefined index
I think it depends upon the developer's requirement.
Are they attempting to determine the existence of a variable/index
entry or are they attempting to determine if the variable/element is
null.
I always declare my variables. So, I don't want to use isset() as they
will be an incorrect test. I use is_null(). Specifically testing the
value. If I've made a mistake and NOT declared the variable (or made a
typo), I want to know. I don't want to hide it with isset()/empty().
--
Richard Quadling
Twitter : EE : Zend
@RQuadling : e-e.com/M_248814.html : bit.ly/9O8vFY
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