Array access on function returns

18 years ago by Kalle Sommer Nielsen — view source — reply

unread

Hey Internals

I've been wondering for quite some time why PHP doesn't allow you to access
arrays when you assign it to a value like in Javascript:

function ArrayTest(Array $range)
{
return($range);
}

$range = Array(1337 => Array('Hello World'));

echo ArrayTest($range)[1337};

I would really like to see this introduced in PHP sometime (Perhaps as
an extra addition to 5.3's new and sleek features).

This is very useful in a few areas and can save a few lines of code
here and there.

unfortunately Im not a C Programmer myself else I've would have
provided a patch for this =/

Cheers

Kalle Sommer Nielsen
Zend Certified Engineer

18 years ago by Sam Barrow — view source — reply

unread

Hey Internals

I've been wondering for quite some time why PHP doesn't allow you to access
arrays when you assign it to a value like in Javascript:

function ArrayTest(Array $range)
{
return($range);
}

$range = Array(1337 => Array('Hello World'));

echo ArrayTest($range)[1337};

I was just about to write an email asking this same exact question this
afternoon. This could be very useful, I don't see any reason not to have
it.

I would really like to see this introduced in PHP sometime (Perhaps as
an extra addition to 5.3's new and sleek features).

This is very useful in a few areas and can save a few lines of code
here and there.

unfortunately Im not a C Programmer myself else I've would have
provided a patch for this =/

Cheers

Kalle Sommer Nielsen
Zend Certified Engineer

18 years ago by Arvids Godjuks — view source — reply

unread

2008/4/18, Sam Barrow sam@sambarrow.com:

Hey Internals

I've been wondering for quite some time why PHP doesn't allow you to
access
arrays when you assign it to a value like in Javascript:

function ArrayTest(Array $range)
{
return($range);
}

$range = Array(1337 => Array('Hello World'));

echo ArrayTest($range)[1337};

I was just about to write an email asking this same exact question this
afternoon. This could be very useful, I don't see any reason not to have
it.

I would really like to see this introduced in PHP sometime (Perhaps as
an extra addition to 5.3's new and sleek features).

This is very useful in a few areas and can save a few lines of code
here and there.

unfortunately Im not a C Programmer myself else I've would have
provided a patch for this =/

Cheers

Kalle Sommer Nielsen
Zend Certified Engineer

--

You now, PHP has it's own way of implementing this - just use list()

function ArrayTest(Array $range) {
return($range);
}

$range = Array('Hello World', 'Hello Me!');
list( , $greetMe) = ArrayTest($range);
echo $greet;

Although you example can't be implemented via list() because you key has
insane value, but usualy we are stuck with few keys with sensible values
like 0, 1, 2, 3. And you should realy return a string then, not an array. I
never had a situation where list() couldn't help. And don't return a big
array because of one value - that will help saving memory :) That's against.

Well, I have an argument also for this one.
It could realy help then returning multidemensional arrays or if an array of
objects is returned

// $object is some object witch contains a lot of other objects in it's
properties
function getObjectList($object) {
$objectList = array();
foreach ($object as $value){
if (is_object($value)){
$objectList[get_class($value)] = $value;
}
}
return $objectList;
}

// Let's assume we know for sure that object with name we know exists
$myObject = new SomeCoolObject();
$result = getObjectList($myObject)['db']->query($sql)->execute();

Well, a stupid one example. So to me it is a little pointless, because you
just can't check if key exists and that will be a warning. So it is very
disputeable if we need it.

18 years ago by Kalle Sommer Nielsen — view source — reply

unread

Hi Arvids

Quoting Arvids Godjuks arvids.godjuks@gmail.com:

2008/4/18, Sam Barrow sam@sambarrow.com:

Hey Internals

I've been wondering for quite some time why PHP doesn't allow you to
access
arrays when you assign it to a value like in Javascript:

function ArrayTest(Array $range)
{
return($range);
}

$range = Array(1337 => Array('Hello World'));

echo ArrayTest($range)[1337};

I was just about to write an email asking this same exact question this
afternoon. This could be very useful, I don't see any reason not to have
it.

I would really like to see this introduced in PHP sometime (Perhaps as
an extra addition to 5.3's new and sleek features).

This is very useful in a few areas and can save a few lines of code
here and there.

unfortunately Im not a C Programmer myself else I've would have
provided a patch for this =/

Cheers

Kalle Sommer Nielsen
Zend Certified Engineer

--

You now, PHP has it's own way of implementing this - just use list()

function ArrayTest(Array $range) {
return($range);
}

$range = Array('Hello World', 'Hello Me!');
list( , $greetMe) = ArrayTest($range);
echo $greet;

I think it would be more suitable to have the array access syntax insted of
the list(, , , $value) syntax, it helps readability for example.

Although you example can't be implemented via list() because you key has
insane value, but usualy we are stuck with few keys with sensible values
like 0, 1, 2, 3. And you should realy return a string then, not an array. I
never had a situation where list() couldn't help. And don't return a big
array because of one value - that will help saving memory :) That's against.

Well, I have an argument also for this one.
It could realy help then returning multidemensional arrays or if an array of
objects is returned

// $object is some object witch contains a lot of other objects in it's
properties
function getObjectList($object) {
$objectList = array();
foreach ($object as $value){
if (is_object($value)){
$objectList[get_class($value)] = $value;
}
}
return $objectList;
}

// Let's assume we know for sure that object with name we know exists
$myObject = new SomeCoolObject();
$result = getObjectList($myObject)['db']->query($sql)->execute();

Well, a stupid one example. So to me it is a little pointless, because you
just can't check if key exists and that will be a warning. So it is very
disputeable if we need it.

I think the usage of this would be in cases where you know the key exists, for
example on getimagesize():

if(!getimagesize($some_image_url)[2] == IMAGETYPE_PNG)
{
die('Please supply a valid url to a png image...');
}

Theres quite alot functions where you need to only get one key and insted of
doing the list() (as written above) it would be nicer with syntax.

Kalle Sommer Nielsen
Zend Certified Engineer

18 years ago by Larry Garfield — view source — reply

unread

Hi Arvids

Quoting Arvids Godjuks arvids.godjuks@gmail.com:

2008/4/18, Sam Barrow sam@sambarrow.com:

Hey Internals

I've been wondering for quite some time why PHP doesn't allow you to

access

arrays when you assign it to a value like in Javascript:

function ArrayTest(Array $range)
{
return($range);
}

$range = Array(1337 => Array('Hello World'));

echo ArrayTest($range)[1337};

I was just about to write an email asking this same exact question this
afternoon. This could be very useful, I don't see any reason not to have
it.

I would really like to see this introduced in PHP sometime (Perhaps as
an extra addition to 5.3's new and sleek features).

This is very useful in a few areas and can save a few lines of code
here and there.

// Let's assume we know for sure that object with name we know exists
$myObject = new SomeCoolObject();
$result = getObjectList($myObject)['db']->query($sql)->execute();

Well, a stupid one example. So to me it is a little pointless, because
you just can't check if key exists and that will be a warning. So it is
very disputeable if we need it.

I think the usage of this would be in cases where you know the key exists,
for example on getimagesize():

if(!getimagesize($some_image_url)[2] == IMAGETYPE_PNG)
{
die('Please supply a valid url to a png image...');
}

Theres quite alot functions where you need to only get one key and insted
of doing the list() (as written above) it would be nicer with syntax.

Kalle Sommer Nielsen
Zend Certified Engineer

It is also useful if returning an object that implements ArrayAccess and
lazy-loads data.

$name = load_something($id)['name'];

If using lazy-loading internally, that could offer very cheap access to the
name property of the "something" object, with only a tiny bit of code. And
it's really no more error prone than:

$something = load($id);
$name = $something['name'];

Presumably you're doing some sort of automated error handling either way
(trigger, exceptions, whatever.)

--
Larry Garfield AIM: LOLG42
larry@garfieldtech.com ICQ: 6817012

"If nature has made any one thing less susceptible than all others of
exclusive property, it is the action of the thinking power called an idea,
which an individual may exclusively possess as long as he keeps it to
himself; but the moment it is divulged, it forces itself into the possession
of every one, and the receiver cannot dispossess himself of it." -- Thomas
Jefferson

18 years ago by Mike Lively — view source — reply

unread

On Fri, Apr 18, 2008 at 10:40 AM, Kalle Sommer Nielsen kalle@php.net
wrote:

Hey Internals

I've been wondering for quite some time why PHP doesn't allow you to
access
arrays when you assign it to a value like in Javascript:

My opinion on features such as this is that they provide too much
opportunity to do things in a far less than optimal way. Another feature
that was brought up (allowing method calls directly on the constructor) has
the same problem.

I realize that this type of functionality seems appealing when you need to
operate on only one index of an array or when you only want to make a single
method call on a newly instantiated object. But it is going to do it at the
cost of readability (imo) and in some cases reduce the speed or flexibility
of the code. If you reference the 'index' of the return value of a function
you in effect have lost access to all other indexes in the array. So, as
soon as you need another index you are forced to either rewrite your code to
not access the method directly as an array, or you have to make another full
function call to pull in the value. The same holds true for chaining
function calls onto constructors.

On the other hand it would be fun trying to track down exactly what you
should be expecting from: $var = new
Class()->call1()->property[0]->call2()[1]->wheeeeeee();

function ArrayTest(Array $range)
{
return($range);
}

$range = Array(1337 => Array('Hello World'));

echo ArrayTest($range)[1337};

I would really like to see this introduced in PHP sometime (Perhaps as an
extra addition to 5.3's new and sleek features).

This is very useful in a few areas and can save a few lines of code here
and there.

unfortunately Im not a C Programmer myself else I've would have provided a
patch for this =/

Cheers

Kalle Sommer Nielsen
Zend Certified Engineer

18 years ago by Wietse Venema — view source — reply

unread

Kalle Sommer Nielsen:

Hey Internals

I've been wondering for quite some time why PHP doesn't allow you
to access arrays when you assign it to a value like in Javascript:

In many languages you get such functionality for free, because their
parsers are written to accept:

expression '[' expression ']'

Thus, any expression that evaluates to an array can have '[]'.
Javascript, Perl and C are just a few examples.

The PHP parser is different. It requires a variable to the left of
'['. Changing this is not as simple as changing one or two YACC
rules.

Wietse

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