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Re: Declaring an array necessary? [message #184975 is a reply to message #184969]

Fri, 21 February 2014 22:03

Daniel Pitts
Messages: 68
Registered: May 2012

Karma:

Member

On 2/21/14 9:56 AM, The Natural Philosopher wrote:
> I was just wondering. Php assumes a varibale exists as soon as it is
> assigned a value, but a function exists to create an array..
> Sop can one just say
>
> $arr['hello']='sexy';
>
> or should there be
>
> $arr=array();
>
> first?
>
>

Necessary, no, but it is still a best practice. It helps with
maintenance later, as well as it clearly states your intent.

Imagine this scenario: You start with

function createMyArray($someData) {

$arr['theData'] = $someData->getX();
$arr['theOtherData'] = $someData->getY();

return $arr;
}

A few weeks later, you get a bug report that you need to only sometimes
add getX().

function createMyArray($someData) {

if ($someData->isFoo()) {
$arr['theData'] = $someData->getX();
}
$arr['theOtherData'] = $someData->getY();

return $arr;
}

Then, you (or someone else) finds out getY() is optional...

function createMyArray($someData) {

if ($someData->isFoo()) {
$arr['theData'] = $someData->getX();
}
if ($someData->isBar()) {
$arr['theOtherData'] = $someData->getY();
}

return $arr;
}

Oh no! You've just introduced a bug where if isFoo and isBar returns
true, then $arr is not set!

Now, if the original author had just added "$arr = []"; things would
have never progressed to this state. It's called defensive programming.
Doing certain things you know aren't strictly necessary now, but might
be necessary, or clear up possible confusion.

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[Message index]

		Declaring an array necessary? By: The Natural Philosoph on Fri, 21 February 2014 17:56
		Re: Declaring an array necessary? By: Christian Stadler on Fri, 21 February 2014 20:04
		Re: Declaring an array necessary? By: Jerry Stuckle on Fri, 21 February 2014 20:48
		Re: Declaring an array necessary? By: The Natural Philosoph on Fri, 21 February 2014 21:32
		Re: Declaring an array necessary? By: Gregor Kofler on Fri, 21 February 2014 21:55
		Re: Declaring an array necessary? By: Tim Streater on Fri, 21 February 2014 22:06
		Re: Declaring an array necessary? By: M. Strobel on Fri, 21 February 2014 21:58
		Re: Declaring an array necessary? By: Daniel Pitts on Fri, 21 February 2014 22:03

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