what is the meaning

[sam]

What is the meaning of this operator:-
=>
Please tell about this.

[BKDotCom]

sam wrote:

What is the meaning of this operator:-
=>
Please tell about this.

Assignment - used in arrays?
http://www.php.net/manual/en/language.types.array.php

[Thomas Mlynarczyk]

Also sprach BKDotCom:

sam wrote:

>What is the meaning of this operator:-
=>

Assignment - used in arrays?

Hm. But why the need for a special operator here? Wouldn't a simple = have
done the job just as well?

Greetings,
Thomas

[NC]

Thomas Mlynarczyk wrote:

>

sam wrote:

What is the meaning of this operator:-
=>

Assignment - used in arrays?

Hm. But why the need for a special operator here? Wouldn't
a simple = have done the job just as well?

Yes, but you'd have to write it differently.

Consider this simple example:

$someArray = array('field1' =1, 'field2' ='two');

If it equivalent to:

$someArray = array();
$someArray['field1'] = 1;
$someArray['field2'] = 'two';

Moreover, the second option might trigger an E_NOTICE, since
you would be trying to assign a value to a not-yet-defined member
of the array...

Cheers,
NC

[Jerry Stuckle]

NC wrote:

Thomas Mlynarczyk wrote:

>>>sam wrote:

What is the meaning of this operator:-
=>

Assignment - used in arrays?

Hm. But why the need for a special operator here? Wouldn't
a simple = have done the job just as well?

Yes, but you'd have to write it differently.

Consider this simple example:

$someArray = array('field1' =1, 'field2' ='two');

If it equivalent to:

$someArray = array();
$someArray['field1'] = 1;
$someArray['field2'] = 'two';

Moreover, the second option might trigger an E_NOTICE, since
you would be trying to assign a value to a not-yet-defined member
of the array...

Cheers,
NC

Actually, the second option is perfectly valid. It's fine to assign to
an array element which hasn't been defined yet. Just don't try to USE
an array element (or any other variable) before it's been defined.

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[Kimmo Laine]

"Thomas Mlynarczyk" <th****@mlynarczyk-webdesign.dewrote in message
news:ek*************@news.t-online.com...

Also sprach BKDotCom:

>sam wrote:

>>What is the meaning of this operator:-
=>

>Assignment - used in arrays?

Hm. But why the need for a special operator here? Wouldn't a simple = have
done the job just as well?

concider the syntax in that case:
$foo = 'bar';
$array1 = array($foo ='zap');
$array2 = array($foo = 'zap');

In the first case you'll get
$array1['bar'] = 'zap'
$foo = 'bar'

but in the second case
$array2[0] = 'zap'
$foo = 'zap'

The results are very different and the reason is clear, the = operator means
a completely different thing than =operator. To get the effect what you
want you need to have another operator. How is php going to know which one
you meant?

And remember it's used in foreach as well:

foreach($array as $key =$val) vs. foreach($array as $key = $val)

Again, very different results, I guess both would be still valid syntax,
although I'm not quite sure about the latter.

The operations that the operators perform are clearly different, that is why
there is a need for two different operators as well.

--
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[Thomas Mlynarczyk]

Also sprach Kimmo Laine:
[Assignment operator in arrays: =>]

>Hm. But why the need for a special operator here? Wouldn't a simple
= have done the job just as well?

consider the syntax in that case:
$array2 = array($foo = 'zap');

Ah, yes, now I see.

Thanks and greetings,
Thomas

[Thomas Mlynarczyk]

Also sprach Jerry Stuckle:

>$someArray = array('field1' =1, 'field2' ='two');

>$someArray = array();
$someArray['field1'] = 1;
$someArray['field2'] = 'two';

Actually, the second option is perfectly valid. It's fine to assign
to an array element which hasn't been defined yet. Just don't try to
USE an array element (or any other variable) before it's been defined.

Come to think of it:
$GLOBALS['notDefinedYet']
and
global $notDefinedYet

The first would give a notice, the second one not. I thought I had read
something about this difference in the manual, but can't find it again.

Also, I have heard about a security issue concerning $GLOBALS: that in some
versions of PHP, it is (was?) possible to overwrite the complete array by
passing a request parameter 'GLOBALS' to the script. Would the global
keyword also be concerned here?

Greetings,
Thomas

[Jerry Stuckle]

Thomas Mlynarczyk wrote:

Also sprach Jerry Stuckle:

>>>$someArray = array('field1' =1, 'field2' ='two');

>>>$someArray = array();
$someArray['field1'] = 1;
$someArray['field2'] = 'two';

>>Actually, the second option is perfectly valid. It's fine to assign
to an array element which hasn't been defined yet. Just don't try to
USE an array element (or any other variable) before it's been defined.

Come to think of it:
$GLOBALS['notDefinedYet']
and
global $notDefinedYet

The first would give a notice, the second one not. I thought I had read
something about this difference in the manual, but can't find it again.

Also, I have heard about a security issue concerning $GLOBALS: that in some
versions of PHP, it is (was?) possible to overwrite the complete array by
passing a request parameter 'GLOBALS' to the script. Would the global
keyword also be concerned here?

Greetings,
Thomas

$GLOBALS['notDefinedYet'] = $x;

will not give a notice.

$x = $GLOBALS['notDefinedYet'];

will. See the difference?
And

global($notDefinedYet);

Doesn't actually use the value. It just declares it to be global.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
js*******@attglobal.net
==================

[Thomas Mlynarczyk]

Also sprach Jerry Stuckle:

$GLOBALS['notDefinedYet'] = $x;
will not give a notice.
$x = $GLOBALS['notDefinedYet'];
will. See the difference?

Yes, of that I was aware.

global($notDefinedYet);
Doesn't actually use the value. It just declares it to be global.

I thought

global $myVar;

was the equivalent of

if ( !isSet( $GLOBALS['myVar'] ) )
{
$GLOBALS['myVar'] = null;
}

$myVar = &$GLOBALS['myVar'];

Greetings,
Thomas

[Jerry Stuckle]

Thomas Mlynarczyk wrote:

Also sprach Jerry Stuckle:

>>$GLOBALS['notDefinedYet'] = $x;
will not give a notice.
$x = $GLOBALS['notDefinedYet'];
will. See the difference?

Yes, of that I was aware.

>>global($notDefinedYet);
Doesn't actually use the value. It just declares it to be global.

I thought

global $myVar;

was the equivalent of

if ( !isSet( $GLOBALS['myVar'] ) )
{
$GLOBALS['myVar'] = null;
}

$myVar = &$GLOBALS['myVar'];

Greetings,
Thomas

I don't think it actually sets $GLOBALS['myVar'] to null, but I could be
wrong. I use globals very rarely.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
js*******@attglobal.net
==================

[Thomas Mlynarczyk]

Also sprach Jerry Stuckle:

I don't think it actually sets $GLOBALS['myVar'] to null, but I could
be wrong.

Well, it seems that $GLOBALS['myVar'] is "set" somehow. At least isSet()
says so, I think. What's important to me here is that I can use something
like

global $myVar;
$this->myVar = is_int( $myVar ) ? $myVar : 0;

instead of

$this->myVar = isSet( $GLOBALS['myVar'] ) && is_int( $GLOBALS['myVar'] )
? $GLOBALS['myVar'] : 0;

I use globals very rarely.

So do I. Just for configuration variables.

Greetings,
Thomas