making new variable from two others

chosun27

I am passing several form fields that are similar to each other to another page for processing in a db. To automate this, I have tried to set up a loop to make the new variables, but it just isn't working.

So, passing field1, field2, field3, etc. to the new page, I would like to then set a loop like this:

for ($n = 1; $n < 10; $n++){
If ('$field'$n == "") {
'$field'$n='empty';
}
}

My question how do I make variables field1, field2, field3 dynamically with the loop.

thanks in advance,
/mark

mrmufin

I'll assume the form method you're using is "POST":

<?php

// Loop through all of the HTTP post variables:
while(list($k,$v)=each($HTTP_POST_VARS)) {
// If the 'trimmed' value is empty, the
// field is incomplete
if(trim($v) == "") {
print("Field $v is empty...");

}
}

If you're using the "GET" method (NOT recommended), loop through the array $HTTP_GET_VARS instead of $HTTP_POST_VARS.

Have fun...

chosun27

Thanks for the suggestion, but that isn't exactly the intent. The important thing is assigning them to variables. So say page 1 has 10 text fields, among others with descriptive names (name, id, blah, blah) that are almost identical in what is put in them. And they are going to be sent to page 2 with POST action on the FORM tag.

Well, on page 2 I want to put them into a db, so I need to assign them variables to add them to the query. But first I want to manipulate them, so I really would like them to be assigned:
$field1
$field2
$field3
$field4
$field5
etc.

But if I'm going to run the same manipulation on them, how come I can't just make those variables in a loop? Why do I have to make each one?
Can't I just have '$field' and attach the loop number $n on the back to make the new variable $field1, $field 2, etc?

$sql_result = query("INSERT INTO $table VALUES ('$id','$title','$body','$prev','$next','$field1','$field2','$field3','$field4','$field5','$field6','$field7','$field8','$field9','$field10')");

etc. etc.

Sorry for the confusion. I hope this conveys what the intent correctly so I can handle this data correctly.

/mark

siwis

Are all your field entries going to be added to the same DB row???

If so then there is no need to "manipulate" them, just give the text fields in your form the "name" that you wish your variable to be passed as.

Therefore, in your form:
<input type="text" name="field1" size="30">
<input type="text" name="field2" size="30">
<input type="text" name="field3" size="30">
<input type="text" name="field4" size="30">
<input type="text" name="field5" size="30">
<input type="text" name="field6" size="30">
<input type="text" name="field7" size="30">
<input type="text" name="field8" size="30">
<input type="text" name="field9" size="30">
<input type="text" name="field10" size="30">

will automatically POST the values of those text fields and assign them variable names:
$field1
$field2
$field3
$field4
$field5
$field6
$field7
$field8
$field9
$field10
without any intervention. Its one of the big time savers in PHP, ie that there is no need to declare variable values when the form is submitted.
$HTTP_POST_VARS['field1'] is automatically assigned to $field1 (unless that variable is already in use and subsequently overwrites your posted value!)

chosun27

That's true. But, unfortunately, I'm not putting the data straight into the db. I am doing some calculations, string manipulation, and changes to the data, then putting it in.

So I really, really would like to do what I've described. This must be super hard, because everyone wants to talk me out of doing it. 😉 When I get to page 2, I realize that all of my variables are assigned automatically and I can just use them one at a time as $field1, $field2, $field3, etc.

But, to work on them before they go into the db, I need to address them one at a time. And going through a loop is much shorter than taking each one separately and running it. If this isn't possible. If combing '$field' and $n are not possible to make $field1, $field2, etc. then I will just have to create a function and run them all through it on page 2. Does anyone know if what I"m trying to do is possible or not?

/mark

siwis

I've no doubt its totally wrong (on this occasion!) and somebody somewhere must know the answer, but the below is a total guess, if I'm correctly assuming what you want to do. (Check field contents in turn for null values and substitute "empty" where those values don't exist???

$fields = array("$field1", "$field2", "$field3", "$field4", "$field5", "$field6", "$field7", "$field8", "$field9", "$field10");

foreach($fields as $field) {
if ($field =="") {
$field = "empty";
$field_str .= "" . $field;
};
};
$field_str = substr("",1);
$field_arr = explode("_", "$field_str")
list($field1, $field2, $field3, $field4, $field5, $field6, $field7, $field8, $field9, $field10) = $field_arr;

siwis

Forgot to say that AFAIK, you cannot concactenate variable names, only their values, which is what I think you were trying to do???

siwis

OOPS! forgot that the if will not add non-empty strings!:

foreach($fields as $field) {
if ($field =="") {
$field = "empty";
$field_str .= "" . $field;
} else {
$field_str .= "" . $field;
};
};
$field_str = substr("",1);
$field_arr = explode("", "$field_str")
list($field1, $field2, $field3, $field4, $field5, $field6, $field7, $field8, $field9, $field10) = $field_arr;

tomhath

What you want are called "variable variables". Here's a link to the documentation (I hope).

http://www.phpbuilder.com/manual/language.variables.variable.php

However, it would be easier do code and much easier to read if you just use a "foreach" loop on an array of field names and the associative array from the POST.

chosun27

Thanks for everyone's help. I think Si is right, you cannot concatenate variable names. But I may be able to do what I need with a combination of all the replies.

thanks!
/mark

SuperDavid

I haven't done it in a while, but from memory, it is possible to make variable names in that way

This code should do the trick:

${"field".$n} = $val;

$field1, $field2 (whatever $n happens to be) should now be variables with value $val.

Hope this helps,

David

tewebe

hi,

here is the page with the explication from phpbuiler:
http://www.phpbuilder.com/columns/robert20000928.php3

and here is my my thread in the "Coding" forum, where i have a problem with variable variables...
http://www.phpbuilder.com/board/showthread.php?s=&threadid=10206376