Re: [PHP] assignment operator works for comparison??
Hi,
Dan wrote:
if($shiny = 0){
This does not compare anyting, it assigns 0 to $shiny
yes i know, but shouldnt this operation return true?
No, it doesn't return true.
The "=" operator returns the value of the expression on its right hand side.
Therefore, the statement given above is equivalent to (as far as the if is
concerned):
if (0) {
because the "=" operator returns 0, the value on its right hand side.
That is why a statement like:
a = b = c = 2
sets all the above variables to 2. Otherwise, if it were to operate the way you
think it should, it would set "c" to 2 and "a" and "b" to "true" ;-).
Hope that clears up things for you.
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Harshdeep Singh Jawanda.
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Re: [PHP] assignment operator works for comparison??
Dan wrote:
This confused me for awhile, because the single equal sign seemed to work
for comparison, but created inexplicable errors in my programs. It seems
strange to me that a successful variable value assignment does not return
true.
example:
?
$shiny = 1;
if($shiny = 0){ echo("This wont print"); }
echo( $shiny ); //this will return 0
?
--Dan
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Okay...
First:
Checking if $shiny equals 0:
if ($shiny == 0) {
But that's already been discussed.
If you _realy_ want to check if the assignment succeeded:
if (($shiny = 0) == 0) {
Try the following example:
-
$a = "Hello";
$b = "Wold";
if ($b == $a)
print "Yes, b equals aBR\n";
else
print "No, b doesn't equal aBR\n";
if (($b = $a) == $a)
print "Yes... now b equals aBR\n";
else
print "Oops... b still doesn't equal a!BR\n";
-
Output will be:
No, b doesn't equal a
Yes... now b equals a
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Re: [PHP] assignment operator works for comparison??
if($shiny = 0){
This does not compare anyting, it assigns 0 to $shiny
echo( $shiny ) // this will return 0
That's normal, you just assign 0 to it ;)
= assignment operator
== comparison operator
py
At 01:53 PM 4/10/01 -0700, you wrote:
This confused me for awhile, because the single equal sign seemed to work
for comparison, but created inexplicable errors in my programs. It seems
strange to me that a successful variable value assignment does not return
true.
example:
?
$shiny = 1;
if($shiny = 0){ echo("This wont print"); }
echo( $shiny ); //this will return 0
?
--Dan
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+ ==
+ Pierre-Yves Lem@ire
+ E-MedHosting.com
+ (514) 729-8100
+ [EMAIL PROTECTED]
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Re: [PHP] assignment operator works for comparison??
if($shiny = 0){
This does not compare anyting, it assigns 0 to $shiny
yes i know, but shouldnt this operation return true?
echo( $shiny ) // this will return 0
That's normal, you just assign 0 to it ;)
= assignment operator
== comparison operator
py
At 01:53 PM 4/10/01 -0700, you wrote:
This confused me for awhile, because the single equal sign seemed to work
for comparison, but created inexplicable errors in my programs. It seems
strange to me that a successful variable value assignment does not return
true.
example:
?
$shiny = 1;
if($shiny = 0){ echo("This wont print"); }
echo( $shiny ); //this will return 0
?
--Dan
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+ ==
+ Pierre-Yves Lem@ire
+ E-MedHosting.com
+ (514) 729-8100
+ [EMAIL PROTECTED]
+ ==
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RE: [PHP] assignment operator works for comparison??
It looks to me like the value of an assignment is the value assigned, as in
Perl. But I don't know for sure, haven't come across this in the manual.
Kirk
-Original Message-
From: Dan [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, April 10, 2001 3:29 PM
To: [EMAIL PROTECTED]
Subject: Re: [PHP] assignment operator works for comparison??
if($shiny = 0){
This does not compare anyting, it assigns 0 to $shiny
yes i know, but shouldnt this operation return true?
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Re: [PHP] assignment operator works for comparison??
You are right, thank you.
It looks to me like the value of an assignment is the value assigned, as
in
Perl. But I don't know for sure, haven't come across this in the manual.
Kirk
if($shiny = 0){
This does not compare anyting, it assigns 0 to $shiny
yes i know, but shouldnt this operation return true?
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Re: [PHP] assignment operator works for comparison??
if($shiny = 0)
This line is the same as
if ((shiny = 0) == TRUE)
It's common error with PHP and C.
You could make use of this like
if ($fp = fopen($filename,'r'))
since this is the same as
if (($fp = fopen($filename,'r')) == TRUE)
code after this line is executed when fopen() success to open file.
Regards,
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Yasuo Ohgaki
""Dan"" [EMAIL PROTECTED] wrote in message
9avrti$olc$[EMAIL PROTECTED]">news:9avrti$olc$[EMAIL PROTECTED]...
This confused me for awhile, because the single equal sign seemed to work
for comparison, but created inexplicable errors in my programs. It seems
strange to me that a successful variable value assignment does not return
true.
example:
?
$shiny = 1;
if($shiny = 0){ echo("This wont print"); }
echo( $shiny ); //this will return 0
?
--Dan
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