[RESOLVED] using braces {}

bookbuyer2000

After 2 days, I still cannot figure out what I am doing wrong. The desired result in visitors browser should be the following:

variable = 5
variable = 10
variable = 15

Here is the php/html code:

<?php
for($i=1;$i<4;$i++){
preg_match("/^\d*/","$c{$i}",$variable);
echo "variable = $variable<BR>";
}
?>
<html>
<body>
<form action="<?=$_SERVER['PHP_SELF']?>" method="post">
<input type="submit">
<input type="hidden" name="c1" value="5abc">
<input type="hidden" name="c2" value="10abc">
<input type="hidden" name="c3" value="15abc">
</form>
</body>
</html>

Thank you :o

bpat1434

You want

echo 'variable = ' . $variable[1] . '<br />';

The entire pattern matched will be in $variable[0], and $variable[1] will contain the first matched sub-match of the regex (i.e. the part in the "()").

bookbuyer2000

I tried your suggestion, and it does not work. Further, I redid the code with print_r($variable) just to see what was in the preg_replace array, and still does not work:

<?php
for($i=1;$i<4;$i++){
preg_match("/^\d*/","$c{$i}",$variable);
print_r($variable);
}
?>
<html>
<body>
<form action="<?=$_SERVER['PHP_SELF']?>" method="post">
<input type="submit">
<input type="hidden" name="c1" value="5abc">
<input type="hidden" name="c2" value="10abc">
<input type="hidden" name="c3" value="15abc">
</form>
</body>
</html>

bpat1434

So what does the print_r() give you?

dagon

why not c[] for c1-3

the foreach loop through the array

Weedpacket

And intval() to get the initial integer part of the value.

leatherback

And just to make sure you are not missing the obvious:
c1 from a posted form would appear on your page through
$c1 = $_POST[c1];

To help yourself, you could make your form like this:

<input type="hidden" name="c[1]" value="5abc">

with the corresponding variable being:

$c[1] = $_POST['c'][1]
//or just:
$c = array
foreach($_POST['c'] as $i => $value)
  {
  $c[$i] = intval($value);
  }
print_r($c);

bookbuyer2000

print_r gives me this result in browser window:
Array ( [0] => 1 ) Array ( [0] => 2 ) Array ( [0] => 3 )

Instead, what I SHOULD be getting is:
Array ( [0] => 5 ) Array ( [0] => 10 ) Array ( [0] => 15 )

So, although everyone's suggestions/help is appreciated, my original question is still unanswered. Am I doing something wrong with the braces {} ??

The "$c{$i}" part in the following line of code should be parsed by PHP as $c1, $c2, and $c3 in my foreach loop, should it not?
preg_match("/^{\d*/","$c{$i}",$variable);}

If PHP reads "$c{$i}" as "$c1" then the line of code would be parsed as:
preg_match("/^{\d/","$c1",$variable);}
-then-
preg_match("/^\d/","$c2",$variable);
-then-
preg_match("/^{\d*/","$c3",$variable);}

and the regex would work.

But, for some reason, the brackets aren't working for me because I've done something wrong with the code, and I don't know what.

dagon

So, although everyone's suggestions/help is appreciated, my original question is still unanswered. Am I doing something wrong with the braces {} ??

if you look at the suggestions above the braces are not required at all

bookbuyer2000

Q: "How do I learn how to blah blah blah?"
A: "Why would you want to blah blah blah?"

I guess I won't get my braces question answered.

...by the way, the suggested code is incorrect... "$c = array" should be, "$c = array();"

... oh, and by the way, the, "And intval()" suggestion won't do what I'm wanting the preg_match to do.

...oh, and by the way, again, the "why not c[] for c1-3 foreach loop through the array" is already looped in my own foreach statement.

Thanks anyway, people.

dagon

...oh, and by the way, again, the "why not c[] for c1-3 foreach loop through the array" is already looped in my own foreach statement.

your not using foreach() in the code you pasted but for(),

[ Mod Edit - bpat1434 ] No need to be rude.

he was rude first.

bookbuyer2000

If I may please rephrase my question. My own question frustrates me. I am appreciative that anyone takes time to help answer. To clarify, I am new to using braces (a "braces newbie" :-) )

So, here is my new and better-phrased question.

How come version "a" works, but version "b" does not work:

VERSION A:
<?php
$c1 = '779abc';
$i = 1;
preg_match("/^{\d*/","$c{$i}",$variable);}
print_r($variable);
?>
// prints Array ( [0] => 1 )

VERSION B:
<?php
$c1 = '779abc';
$i = 1;
preg_match("/^{\d*/","$c{$i}",$variable);}
print_r($variable);
?>
// prints what I want: Array ( [0] => 779 )

Hopefully my question has been phrased better. Thank you. :o

NogDog

If you really, really want to use the braces stuff, it would be:

${"c$i"}

However, your code will be simpler and easier to maintain if you go with the suggestion of using array-style names for your form elements, then just use the applicable sub-array within the $POST or $GET array.

<?php
if(!empty($_POST['c']))
{
   foreach($_POST['c'] as $index => $value)
   {
      $variable = (int)$value;
      printf("<p>c[%d]: %s</p>\n", $index, $variable);
   }
}
?>
<html>
<body>
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
<fieldset>
<legend>Test</legend>
<input type="submit">
<input type="hidden" name="c[1]" value="5abc">
<input type="hidden" name="c[2]" value="10abc">
<input type="hidden" name="c[3]" value="15abc">
</fieldset>
</form>
</body>
</html>

bpat1434

To answer your question, no you weren't using them right.

UNLESS you have register_globals on (which you shouldn't, security risk) then your code would be looking for an unknown variable and throwing errors. I've reworked you code and it works in PHP 5 without errors.

<?php

for($i=1;$i<4;$i++){
	$var = 'c' . $i;
	preg_match("/^(\d*)/",$_POST[$var], $variable);
	echo "variable = " . $variable[1] . "<BR>";
}
?>
<html>
<body>
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
<input type="submit" name="submit" value="submit">
<input type="hidden" name="c1" value="5abc">
<input type="hidden" name="c2" value="10abc">
<input type="hidden" name="c3" value="15abc">
</form>
</body>
</html>

Note that I created an intermittent variable "$var = 'c' . $i;". This is only to get the variable name set. You could have just as easily done:

$_POST['c' . $i]

It would seem you were confusing concatenation with variable variables

Technically neither version works:

[b]Version A[/b]

Notice: Undefined variable: c in /home/brett/public_html/variable_variables.php on line 25
Array ( [0] => 1 )


[b]Version B[/b]

Notice: Undefined variable: c in /home/brett/public_html/variable_variables.php on line 31
Array ( [0] => 1 )

You're missing parenthesis to catch the digits in the preg_match pattern. Not to mention that the array key 0 will never match just "779", it will match the entire pattern where a match was found. The key 1 would be the one which matches 779.

bookbuyer2000

...oops I accidentally re-posted my question, and I see lots of answers which I shall now read. Thank you all so much for answering. I'm going to carefully read the answers now. Thank you!!

NogDog

Here's a more narrowly focused script to demonstrate the difference between how you were trying to use braces and what I suggested:

<pre><?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
$cn = '779abc';
$i = 'n';
echo "Test 1:\n";
echo $c{$i};
echo "\n\nTest 2:\n";
echo ${"c$i"};
?></pre>

Output:

Test 1:


Notice:  Undefined variable: c in C:\wamp\www\test\test.php on line 7



Test 2:
779abc

leatherback

bookbuyer2000 wrote:
Q: "How do I learn how to blah blah blah?"
A: "Why would you want to blah blah blah?"

I guess I won't get my braces question answered.

...by the way, the suggested code is incorrect... "$c = array" should be, "$c = array();"

... oh, and by the way, the, "And intval()" suggestion won't do what I'm wanting the preg_match to do.

...oh, and by the way, again, the "why not c[] for c1-3 foreach loop through the array" is already looped in my own foreach statement.

Thanks anyway, people.

No need to get aggressive mate. On this forum a lot of people misuse code& functions, and seem to miss the obvious at times. Therefore we start of by finding out whether the person requires what he/she think they need. More than 90% of the cases there are no restrictions on how a code could be reworked. So if a solution if several times easier to maintain in a different form, that will be suggested.

In your case, it looks like again like a typical situation that the path you have taken was not required.

PS: Yes. I do make typos in my posts at times. Sorry for the missing brackets.

bookbuyer2000

No aggression intended. This is one of my favorite boards, and I have the utmost admiration for you and others that are PHP experts. Further, you are indeed correct in that part of what makes this such a good board/forum is the alternative suggestions posed by the experts.

As a newbie, it's possible to become frustrated at having learned something so simple (such as how to use braces), and then go to implement it, and it doesn't work because of some little mistake I made. Anyway, thank you for your input, and in the future, I'll try to word my questions even better.

(now I have to figure out how to put the "RESOLVED" thingy on my post.... 😕