Re: [PHP] Arrays within classes
On Friday, April 5, 2002, at 03:00 PM, Brian McLaughlin wrote: > My problem is that when I assign an empty array to a variable, I get > different results depending on whether that variable is in an object or > not. > In the case of assigning $a=array(); outside of an object, each element > of > the array is empty (as I expected). But when assigning > $this->$words=array(); results in $this->$words["Amy"] (or any other > element > for that matter) already being assigned an array. And if I look at the > elements of those arrays, they are also initialized to arrays. I don't > know > how deep it goes. Brian, Sorry to take so long to get back to you about this -- my inbox is very cluttered. The only thing I can think of is to ask you if you are sure you need the second buck in "$this->$words = array()" -- perhaps you have a reason for using a variable as the name of the class variable, but I would probably write it as "$this->words = array()". If that is not the source of your problem, re-post to the list and perhaps Lars Torben or one of the gurus will spot this idiosyncracy and have an explanation. or if you have already solved it, can you let me know what it was? I'm starting to do some object stuff in PHP and need to know about strange behavior like this. Regards, Erik Erik Price Web Developer Temp Media Lab, H.H. Brown [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Arrays within classes
Thank you!! Now I need to figure out how to put all this hair back in my head. Brian "Rick Emery" <[EMAIL PROTECTED]> wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > I corrected the syntax errors Erik found and added var_dump() after each $t > equation/assignment > > The problem is that you refer to $test->words. You should refer to > $test->words > BIG DIFFERENCE > > $test->words means find the value of $words and look for that variable in > $test. That is, if $words ="abc", > then $test->$words means $test->abc > > Yes, it's in the manual > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Arrays within classes
Hi Erik
Thanks for the reply. I'm not sure how I missed the opening { in my
message -- I copy/pasted the code. But the opening { is definitely there in
the code -- I'd get a nice error message if it weren't. I believe it's OK
to have a ; after the class def end-brace, but I removed it and I got the
same symptoms. I also believe it's OK to not have the () in the "new test"
instance assignment as long as my constructor takes no parameters. I added
the (), and didn't get different results.
I'm not sure what you mean when you say "Don't you want to perform your
error-testing functions on the instances?" I'm trying to initialize some
class-arrays in the constructor. I put some echo"" statements in there to
try and figure out what was going on. The example is just an example -- the
smallest piece of code I could make (presumably) that would exhibit the
symptoms. The purpose for the "real" class I'm working with is to
encapsulate several arrays (one of which is an array of arrays) along with a
few other variables into a data class that can be put/retrieved as a single
object into the session. The reason is so that all the code that builds
these arrays only happens when the user hits the first page. Then the
arrays are available from the session on subsequent hits.
My problem is that when I assign an empty array to a variable, I get
different results depending on whether that variable is in an object or not.
In the case of assigning $a=array(); outside of an object, each element of
the array is empty (as I expected). But when assigning
$this->$words=array(); results in $this->$words["Amy"] (or any other element
for that matter) already being assigned an array. And if I look at the
elements of those arrays, they are also initialized to arrays. I don't know
how deep it goes.
The way I noticed this at first was like this: In the constructor, I'm
reading phrases from a file and putting each word into the $words array, and
assigning $words[$word]=array($phrasenum); (so each word in the $words
array gives back an array containing the id's of the phrases it appears in)
When I come across a word that I've already added for phrase 1 in phrase 2,
I expect it to already exist in the array, because I put it there the first
time I came across the word in phrase 1. Instead, Every element is
pre-assigned to another array, and so the code gets confused, thinking that
it has entries for any word I care to index the array with.
Sorry for the long drawn-out message. Maybe it will help?
Thanks
Brian
"Erik Price" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> I might be completely mistaken here, but it looks like there are a few
> errors in your code:
>
> - No starting brace for the test() method
> - semi-colon used after class def end-brace
> - no parentheses after "new test" instance assignment
>
> Don't you want to keep your class as general as possible, and perform
> your error-testing functions on the instances? It's hard for me to tell
> what kind of data you are trying to represent with this class. My
> advice is that, even if it seems unnecessarily didactic, you use some
> sort of actual object to help you visualize what you are trying to do
> with this class, like Person() or something -- it helps. I can't figure
> out what this class is even supposed to do.
>
>
> Erik
>
>
> Erik Price
> Web Developer Temp
> Media Lab, H.H. Brown
> [EMAIL PROTECTED]
>
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RE: [PHP] Arrays within classes
Corrected typo: The problem is that you refer to $test->$words. You should refer to $test->words BIG DIFFERENCE $test->$words means find the value of $words and look for that variable in $test. That is, if $words ="abc", then $test->$words means $test->abc -Original Message- From: Rick Emery [mailto:[EMAIL PROTECTED]] Sent: Friday, April 05, 2002 1:28 PM To: 'Brian McLaughlin'; [EMAIL PROTECTED] Subject: RE: [PHP] Arrays within classes I corrected the syntax errors Erik found and added var_dump() after each $t equation/assignment The problem is that you refer to $test->words. You should refer to $test->words BIG DIFFERENCE $test->words means find the value of $words and look for that variable in $test. That is, if $words ="abc", then $test->$words means $test->abc Yes, it's in the manual -Original Message- From: Brian McLaughlin [mailto:[EMAIL PROTECTED]] Sent: Friday, April 05, 2002 12:21 PM To: [EMAIL PROTECTED] Subject: [PHP] Arrays within classes This is driving me crazy! I've created a class to hold data so I can just put the object into the session rather than saving off each piece of data separately. But I'm getting odd results from the arrays in my class that I can't explain. Here's a hunk of code that demonstrates: $words; echo "1: words = $t\n";// Shows that $words is empty $this->$words = array(); $t = $this->$words; echo "2: words = $t\n"; // Shows that $words is an array $t = $this->$words["Amy"]; echo "3: words[Amy] = $t\n"; // Shows that $words["Amy"] is also an array -- WHAT?? } }; ### Declare a$ to be an array echo "1: a = $a\n"; // Shows that $a is empty $a = array(); $t = $a; echo "2: a = $t\n"; // Shows that $a is an array $t = $a["Amy"]; echo "3: a[Amy] = $t\n"; // Shows that $a["Amy"] is also empty -- GOOD echo ""; ## Instantiate a test object $test = new test; ?> When I declare a member variable ($words) within the class and then assign to it an empty array, it seems all the elements of that array are also arrays -- they should be empty. When I do the same thing outside of a class ($a), I get the results I expect. Can anyone tell me why that is? Thanks Brian [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
RE: [PHP] Arrays within classes
I corrected the syntax errors Erik found and added var_dump() after each $t equation/assignment The problem is that you refer to $test->words. You should refer to $test->words BIG DIFFERENCE $test->words means find the value of $words and look for that variable in $test. That is, if $words ="abc", then $test->$words means $test->abc Yes, it's in the manual -Original Message- From: Brian McLaughlin [mailto:[EMAIL PROTECTED]] Sent: Friday, April 05, 2002 12:21 PM To: [EMAIL PROTECTED] Subject: [PHP] Arrays within classes This is driving me crazy! I've created a class to hold data so I can just put the object into the session rather than saving off each piece of data separately. But I'm getting odd results from the arrays in my class that I can't explain. Here's a hunk of code that demonstrates: $words; echo "1: words = $t\n";// Shows that $words is empty $this->$words = array(); $t = $this->$words; echo "2: words = $t\n"; // Shows that $words is an array $t = $this->$words["Amy"]; echo "3: words[Amy] = $t\n"; // Shows that $words["Amy"] is also an array -- WHAT?? } }; ### Declare a$ to be an array echo "1: a = $a\n"; // Shows that $a is empty $a = array(); $t = $a; echo "2: a = $t\n"; // Shows that $a is an array $t = $a["Amy"]; echo "3: a[Amy] = $t\n"; // Shows that $a["Amy"] is also empty -- GOOD echo ""; ## Instantiate a test object $test = new test; ?> When I declare a member variable ($words) within the class and then assign to it an empty array, it seems all the elements of that array are also arrays -- they should be empty. When I do the same thing outside of a class ($a), I get the results I expect. Can anyone tell me why that is? Thanks Brian [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Arrays within classes
I might be completely mistaken here, but it looks like there are a few
errors in your code:
- No starting brace for the test() method
- semi-colon used after class def end-brace
- no parentheses after "new test" instance assignment
Don't you want to keep your class as general as possible, and perform
your error-testing functions on the instances? It's hard for me to tell
what kind of data you are trying to represent with this class. My
advice is that, even if it seems unnecessarily didactic, you use some
sort of actual object to help you visualize what you are trying to do
with this class, like Person() or something -- it helps. I can't figure
out what this class is even supposed to do.
Erik
On Friday, April 5, 2002, at 01:21 PM, Brian McLaughlin wrote:
> This is driving me crazy! I've created a class to hold data so I can
> just
> put the object into the session rather than saving off each piece of
> data
> separately. But I'm getting odd results from the arrays in my class
> that I
> can't explain. Here's a hunk of code that demonstrates:
>
>
> class test {
>
> var $words;
>
> function test()
>
>
> $t = $this->$words;
> echo "1: words = $t\n";// Shows that $words is empty
> $this->$words = array();
> $t = $this->$words;
> echo "2: words = $t\n"; // Shows that $words is an array
> $t = $this->$words["Amy"];
> echo "3: words[Amy] = $t\n"; // Shows that $words["Amy"] is
> also an
> array -- WHAT??
> }
> };
>
> ### Declare a$ to be an array
> echo "1: a = $a\n"; // Shows that $a is empty
> $a = array();
> $t = $a;
> echo "2: a = $t\n"; // Shows that $a is an array
> $t = $a["Amy"];
> echo "3: a[Amy] = $t\n"; // Shows that $a["Amy"] is also
> empty -- GOOD
>
> echo "";
>
> ## Instantiate a test object
> $test = new test;
>
> ?>
>
> When I declare a member variable ($words) within the class and then
> assign
> to it an empty array, it seems all the elements of that array are also
> arrays -- they should be empty. When I do the same thing outside of a
> class
> ($a), I get the results I expect.
>
> Can anyone tell me why that is?
>
> Thanks
>
> Brian
> [EMAIL PROTECTED]
>
>
>
>
> --
> PHP General Mailing List (http://www.php.net/)
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>
Erik Price
Web Developer Temp
Media Lab, H.H. Brown
[EMAIL PROTECTED]
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