foreach

stew

hey there guys...

im really having trouble understanding the foreach()...

im using it to echo() several inputs (all of which inputs are called "var" and are different integers), from a form onto another page ... i have figured out that i can to use foreach() to display them correctly, but as i say i have no idea how to use it properly...

the manual says...

foreach(array_expression as $value) { statement }

and i think (from my research), that array_expression is the input name from the form, i.e. "var". i have looked for a few other tutorials on this and i have no idea where $value comes from.

any wee bits of info - that a newbie can understand - on foreach() would be much appreciated!

thank you...

WinterDragon

well ok look here...


#Lets create an array.

$array = array("First", "Second", "Third");

#Now lets do the foreach.
#Array goes first, what it does... is say ok first value goes into $value
#then does whatever you want.

#Ok easier way, It loops through each piece of the array, starting at the begining, and assigns each piece to $value, one at a time, then does whatever you need with it.
foreach ($array as $value) {
echo "$value<br>";
}
#Here I echo the value out.

daynah

The function foreach() is only used when a variable is of type array. What is an array? It's a collection of related data. Say you have an array called $testscores.

The array data would look like this:
$testscores[0] = 95;
$testscores[1] = 86;
$testscores[2] = 58;
$testscores[3] = 87;
$testscores[4] = 78;

It could also look like this:

$testscores = array(95, 86, 58, 87, 78);

As for your form, the data you submit goes into an array called $_POST.

So if you had fields like: name, age, location -- Your array would look like this:
$POST["name"] = "name submitted";
$POST["age"] = 50;
$_POST["location"] = 'USA';

The foreach expression you would use in this case is:
foreach(array_expression as $key => $value) statement

The reason is that this array is an "associative array," meaning, instead of numbers as the key, expressions (like name, age.. ) are used instead.

Finally, your could to print out the data in the $POST array is this:

foreach($_POST as $k => $v) {
    print "\$_POST[$k] => $v.\n";
}

*note: $HTTP_POST_VARS has been deprecated, which is why I used $_POST. Read the part about forms here for more details.

I hope this helped. 🙂

stew

so if all the data from the form goes into the array $POST, i would have like 5 or 6 of $POST["var"]

so can i have a sub array, as it were, like $_POST["var["$id"]"] (if you see what im getting at...) where the $id is the value if each input called "var" from the form?

...i think i just really confused myself!

stew

or would an array be created for the original values of the form to be $var[1], $var[4], $var[5], ...etc?

daynah

Wait.. I'm a little bit confused. How come all your variables are called var?

Shouldn't it be $POST["id"], $POST["var2"], $POST["var3"], $POST["var4"], etc. ?

The keys to the array $_POST are what you named the variables in your form.

For example, your form uses:

When the submit button is clicked, you would have the following values: $POST["id"], $POST["var2"], $_POST["var3"]

Is this more clear?

stew

the only inputs in the form are checkboxes, which have been looped using a while()

 
<form>
while (etc....) {


echo ("<input type=\"checkbox\" name=\"var\" value=\"$id\">");

}
<input type=submit>
</form>

$id is being looped in the while()!

the reason it is constructed like this is because a user is inserting into the database, and the while() above is fetching the arrays that haven't been authorised to go on the general display yet.

the idea of the checkbox is to confirm that the post can be viewed by the vistors to the site. the $var would then be passed onto the next page (with the value $id) where another sql command is carried out -
such as...

UPDATE table SET etc.... WHERE field = '$var' ;

the only bit i really need help with is the foreach() on the action of the form to loop the different $var 's

so at the moment, on the next page (the action of the form), there will be serveral $_POST["var"] and no way to distinguish them from one another, which im assuming is wrong...

i hope this is clearer...