What's wrong with this simple line of code?

[fishmonger1972]

I'm a librarian trying to put a finishing touch on an online materials
catalog. The line below seems to do nothing in my program.. And I
don't get any error messages. So, I'm very perplexed because it
doesn't work as I'd like.

I'm trying to see if $book_review_url is defined.. then if it is I
want it to make 'Click here for reviews for $title' to be hyperlinked
by the url that is in the database in $book_review_url. Any help
would be appreciated!
<?php if (defined($book_review_url)) echo "<a href=\"$book_review_url
\">Click here for reviews for $title on Amazon.com</a>"; ?>

[John C. Frickson]

On 2007-03-09 17:03, fi************@gmail.com wrote:

I'm a librarian trying to put a finishing touch on an online materials
catalog. The line below seems to do nothing in my program.. And I
don't get any error messages. So, I'm very perplexed because it
doesn't work as I'd like.

I'm trying to see if $book_review_url is defined.. then if it is I
want it to make 'Click here for reviews for $title' to be hyperlinked
by the url that is in the database in $book_review_url. Any help
would be appreciated!
<?php if (defined($book_review_url)) echo "<a href=\"$book_review_url
\">Click here for reviews for $title on Amazon.com</a>"; ?>

defined() only works for constants, not variables.

If you know that the variable $book_review_url exists and you
want to just check if it's not empty, use
if ($book_review_url != "")

If you don't know if the variable even exists, use
if (exists($book_review_url) && $book_review_url != "")

[Christoph Burschka]

John C. Frickson wrote:

If you don't know if the variable even exists, use
if (exists($book_review_url) && $book_review_url != "")

exists() isn't mentioned anywhere in the PHP manual - I assume you mean isset()...

--cb

[Geoff Berrow]

Message-ID: <55*************@mid.dfncis.defrom Christoph Burschka
contained the following:

>If you don't know if the variable even exists, use
if (exists($book_review_url) && $book_review_url != "")

exists() isn't mentioned anywhere in the PHP manual - I assume you mean isset()...

or you can just do

if (!empty( $book_review_url )){
,,,
}

--
Geoff Berrow (put thecat out to email)
It's only Usenet, no one dies.
My opinions, not the committee's, mine.
Simple RFDs http://www.ckdog.co.uk/rfdmaker/

[boclair]

fi************@gmail.com wrote:

I'm a librarian trying to put a finishing touch on an online materials
catalog. The line below seems to do nothing in my program.. And I
don't get any error messages. So, I'm very perplexed because it
doesn't work as I'd like.

I'm trying to see if $book_review_url is defined.. then if it is I
want it to make 'Click here for reviews for $title' to be hyperlinked
by the url that is in the database in $book_review_url. Any help
would be appreciated!
<?php if (defined($book_review_url)) echo "<a href=\"$book_review_url
\">Click here for reviews for $title on Amazon.com</a>"; ?>

if (ISSET($book_review_url) {}

or, depending,

if ($book_review_url) {}

Louise

[Mike Russell]

<fi************@gmail.comwrote in message
news:11********************@64g2000cwx.googlegroup s.com...

I'm a librarian trying to put a finishing touch on an online materials
catalog. The line below seems to do nothing in my program.. And I

....

<?php if (defined($book_review_url)) echo "<a href=\"$book_review_url
\">Click here for reviews for $title on Amazon.com</a>"; ?>

Others have mentioned use of isset(). Two other errors are that you should
not escape the quotes in this situation, and use . to concatenate strings:

echo "<a href=" . $book_review_url . ">Click here for reviews for $title on
Amazon.com</a>"
(watch for line breaks in this posted message)

There are some things you can do to make writing code like this easier. You
can use an IDE with a built-in syntax checker to find errors as you type
them in, instead of later - eclipse is my current favorite, and there are
other excellent ones, or use php -l to do a quick syntax check. Also, copy
code that others have written, rather than create it yourself from scratch.
--
Mike Russell
www.curvemeister.com/forum/

[Rik]

Mike Russell <RE*********@Curvemeister.comRE-MOVEwrote:

<fi************@gmail.comwrote in message
news:11********************@64g2000cwx.googlegroup s.com...

>I'm a librarian trying to put a finishing touch on an online materials
catalog. The line below seems to do nothing in my program.. And I

...

><?php if (defined($book_review_url)) echo "<a href=\"$book_review_url
\">Click here for reviews for $title on Amazon.com</a>"; ?>

Others have mentioned use of isset(). Two other errors are that you
should
not escape the quotes in this situation, and use . to concatenate
strings:

echo "<a href=" . $book_review_url . ">Click here for reviews for $title
on
Amazon.com</a>"
(watch for line breaks in this posted message)

There are some things you can do to make writing code like this easier..
You
can use an IDE with a built-in syntax checker to find errors as you type
them in, instead of later - eclipse is my current favorite, and there are
other excellent ones, or use php -l to do a quick syntax check.

Check, I'm using UltraEdit myself, and a quick Ctrl+Shift+1 really helps
in syntax checking (And configurable tools rool. I do not need expensive
packages as long as can use any custom tool I desire :-)

Also, copy code that others have written, rather than create it yourself
from scratch.

Ammendment: you _do_ have to understand the code others have written IMHO.
--
Rik Wasmus
Posted on Usenet, not any forum you might see this in.
Ask Smart Questions: http://tinyurl.com/anel

[Geoff Berrow]

Message-ID: <4F*****************@newssvr27.news.prodigy.netfro m Mike
Russell contained the following:

><?php if (defined($book_review_url)) echo "<a href=\"$book_review_url
\">Click here for reviews for $title on Amazon.com</a>"; ?>

Others have mentioned use of isset(). Two other errors are that you should
not escape the quotes in this situation, and use . to concatenate strings:

echo "<a href=" . $book_review_url . ">Click here for reviews for $title on
Amazon.com</a>"
(watch for line breaks in this posted message)

Umm...ITYM
echo '<a href="' . $book_review_url . '">Click here for reviews for
'.$title.' on Amazon.com</a>';

But being lazy I'd usually do

echo "<a href='$book_review_url '>Click here for reviews for $title on
Amazon.com</a>";

--
Geoff Berrow (put thecat out to email)
It's only Usenet, no one dies.
My opinions, not the committee's, mine.
Simple RFDs http://www.ckdog.co.uk/rfdmaker/

[Jerry Stuckle]

Mike Russell wrote:

<fi************@gmail.comwrote in message
news:11********************@64g2000cwx.googlegroup s.com...

>I'm a librarian trying to put a finishing touch on an online materials
catalog. The line below seems to do nothing in my program.. And I

...

><?php if (defined($book_review_url)) echo "<a href=\"$book_review_url
\">Click here for reviews for $title on Amazon.com</a>"; ?>

Others have mentioned use of isset(). Two other errors are that you should
not escape the quotes in this situation, and use . to concatenate strings:

echo "<a href=" . $book_review_url . ">Click here for reviews for $title on
Amazon.com</a>"
(watch for line breaks in this posted message)

Actually, the quotes need to be escaped. They are part of the HTML
code. $book_review_url will still be expanded. And he isn't doing
string concatenation. So no '.' is required.

The result should look similar to:

<a href="http://www.example.com/book_reviews">...

There are some things you can do to make writing code like this easier. You
can use an IDE with a built-in syntax checker to find errors as you type
them in, instead of later - eclipse is my current favorite, and there are
other excellent ones, or use php -l to do a quick syntax check. Also, copy
code that others have written, rather than create it yourself from scratch.

No syntax errors. Just a problem with not using isset().

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

[Mike Russell]

"Jerry Stuckle" <js*******@attglobal.netwrote in message
news:pY******************************@comcast.com. ..

[re correction of my correction]

Actually, the quotes need to be escaped. They are part of the HTML code.
$book_review_url will still be expanded. And he isn't doing string
concatenation. So no '.' is required.

The result should look similar to:

<a href="http://www.example.com/book_reviews">...

Right you are Jerry. I stand corrected. This will save me some typing in
the future. :-)
--
Mike Russell
www.curvemeister.com/forum/