How to assign a value to a variable in an array?

we5inelgr

Hi all,

The relavent code here for the question below.

$POSTArray = array ($_POST['a'], $_POST['b'], $_POST['c'], $_POST['d'], $_POST['e'], $_POST['f'], $_POST['g'], $_POST['h'], $_POST['i']); //** Each may, or may not have a value **//
$flagArray = array ($aFlag, $bFlag, $cFlag, $dFlag, $eFlag, $fFlag, $gFlag, $hFlag, $iFlag); //** All of these do not have a value yet **//

$p = count($POSTArray);

for ($a=0;$a<$p;$a++) {
    if ($POSTArray[$a] != "") { 
	list($someOtherReturnedVar, $flag) = the_function ( $POSTArray[$a] );  //** Send info to the function. $flag is sent back as either "Y" or "N" **//
        $flagArray[$a] = $flag; //** This is what isn't working, but is the "jist" of what I'm looking for **//
    } 
}

echo "aFlag = ".$aFlag;

If $_POST['a'] contains a value, I want to set the resulting flag that comes out of the function to $aFlag (or is post b isn't null, then $bFlag should be set to $flag, etc. etc).

However, when _POST['a'] does contain something, and then I echo out $aFlag, it's empty.

How do I set the corresponding variable in the $flagArray to the $flag value?

Thanks.

rbrown56

Well you have a few things wrong...

1) You don't need to set the $POST['a'] to an array, that is an array already... the $POST array.

2) if you use a $POST you should check to see if it isset() otherwise it will throw an error.

if(!isset($_POST['a']) {
$_POST['a'] = '';
} else {
// process the rest of the script 
}

3) If you are using a $_POST you should always check the data in addition, so someone can't insert code into your script. Data validation is an integral part of working with forms. Not only can invalid submitted data lead to security problems, but it can also break your webpage.

4) You can't use variables to set an array like this.

$flagArray = array ($aFlag, $bFlag, $cFlag, $dFlag, $eFlag, $fFlag, $gFlag, $hFlag, $iFlag); 

//It needs to be:
$flagArray[] = $aFlag;
$flagArray[] = $bFlag;
//etc...

// to get output you would use:
echo $flagArray['0'];

// would output the value you set for $aFlag

echo $flagArray['1'];

// would output the value you set for $bFlag

//Or you can do it this way:

$flagArray['aFlag'] = $aFlag;
$flagArray['bFlag'] = $bFlag;

// to get output you would use:
echo $flagArray['aFlag'];


// would output the value you set for $aFlag

You should do some reading on arrays and how to sanitize and validate your data so you aren't spinning your wheels... Or getting into trouble...

we5inelgr

Thanks for the reply.

Yes, I have client side (js) and server side (php) data validation and sanitation going on prior to this snippet.

There are about 3 times more post variables that what I'm working with in this case. In order to not have to spin through every post var and single out the ones I'm looking for with either a really long if ($varA || $varB || $varC etc...) or putting the
vars I'm interested in into an array anyway, I thought I'd go with what I've got for now for doing additional processing on this subset of post vars.

I also didn't want to have to do this:

if(!isset($_POST['a']) { 
$_POST['a'] = ''; 
} else { 
// process the rest of the script  

}
if(!isset($_POST['b']) { 
$_POST['b'] = ''; 
} else { 
// process the rest of the script  

}
if(!isset($_POST['c']) { 
$_POST['c'] = ''; 
} else { 
// process the rest of the script  

}
if(!isset($_POST['d']) { 
$_POST['d'] = ''; 
} else { 
// process the rest of the script  

}
...etc.

For now, I got it working by using references:

$flagArray = array (&$aFlag, &$bFlag, &$cFlag, &$dFlag, &$eFlag, &$fFlag, &$gFlag, &$hFlag, &$iFlag);

rbrown56

you should think about writing a foreach, while or even better... a class, to process your data, then you can add as many fields in your form as you want.

As far a references... even though they are slightly faster than a function, there are also other reasons why you should avoid using references.
Though they can simplify several algorithms, especially when you are manipulating two or more data structures that must have the same underlying data:

1) They will cause functions to have side-effects. You should, in general, avoid functions with side-effects, as they make your program more unpredictable ("WTF, how the hell did this did this value get here?" More than likely the culprit is a function with references that modified its parameters.)

2) They cause bugs. If you make a variable a reference, you must remember to unset it before assigning it a value, unless you want to change the underlying value of the reference set. This happens after you run a foreach loop by reference and then re-use the loop variable.