Accessing constructed variables

Developers Programming
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#1

Hi,

I have couple of problems with accessing variables and could not find any relevant post on the subject. Appreciate if any one has faced these issues and found some workarounds:

Background: I have a table with say 10 fields amount_1, amount_2, … amount_10. and I need to access these fields using a for loop and assign some computed values.

When I directly try {amount_1}=999; it works, however if I construct a variable for e.g.
$i=1;
$tmp=’{amount_’.$i.’}=999;’;
and do an
eval($tmp); – it does not work. Further if I do an echo $tmp; – it shows a space in between { braces – like – { amount_1}=999;

This is strange SC is adding a blank space after {

I have tried many events including OnLoad.

Second issue is what is the best way to do a total of these fields – which event.

Apart from the above 10 amount fields I have a total field. How do I display the total in the form whenever any of these amount are changed / update.

Regards,
Chetan

#2

anyone able to get eval work?

below is my code and it doesn’t take effect and no error as well

$tmp = "{name_first}='abc';";
eval($tmp);
#3

[QUOTE=weilies;27722]anyone able to get eval work?

below is my code and it doesn’t take effect and no error as well[/QUOTE]

When there are issues, then eval will not return an error message. Also despite what you want to do I would try to find another solution, like putting the values in an array and process. To allow a program to put php code in a variable to be executed is a security risk and should be avoided at all times imho. See http://php.net/manual/en/function.eval.php.

in your sample:

$arr = array($amount_1, $amount2, %amount3);
foreach($arr as $elem) {
// do your thing.
}

#4

hi, i managed to make it worked!
here is the code

$myname = “here is my name…”;
eval(’{name_first} = ‘’ . $myname . ‘’;’);

i tried with many permutation and finally get one working! hurray!

Thanks Albert

#5

hi Albert, i got stuck again… sorry for request further helps :slight_smile:

Example 1: working

$field = 'name_first';
$name = 'weilies';

// code below able to update page’s name_first field to ‘weilies’ once loaded
eval(’{name_first} = ‘’ . $name . ‘’;’);

Example 2: working

$field = 'name_first';
$name = 'weilies';

$cmd = '{name_first} = \'' . $name . '\';';

    // code below able to update page's name_first field to 'weilies' once loaded
eval($cmd);

Example 3: not working

$field = 'name_first';
$name = 'weilies';

$cmd = '{' . $field . '} = \'' . $name . '\';';

    // code below doesn't update field page
eval($cmd);

Dear gurus, i need some helps here. I can’t tell what so different for both example 2 and 3, i need the field_name to be dynamically assign via value (example 3). But i have no luck to make it work.

#6

I don’t know, I don’t use eval. Why can’t you use my approach of creating an array. It’s safe and by far more conveniant imho. See: http://php.net/manual/en/language.types.array.php

#7

Check the generated code, that should make it clear why it doenst work (use view source).

#8

This information really useful.

#9

Did you manage to solve Example 3?

good evenning

Did you manage to solve Example 3?

Thank You

[QUOTE=weilies;27813]hi Albert, i got stuck again… sorry for request further helps :slight_smile:

Example 1: working

Example 2: working

Example 3: not working

Dear gurus, i need some helps here. I can’t tell what so different for both example 2 and 3, i need the field_name to be dynamically assign via value (example 3). But i have no luck to make it work.[/QUOTE]