The PHP for() loop

Sat, 28 January, 2006 – 11:59 pm

And another loop for you to try is the for() loop. This repeats for a specified number of times.

[source:php]$num = 10
for ($i=0; $i < $num; $i++) {
print $num;
print "
";
}
[/source]

This will print out the numbers 0 to 9, each on a new line. With this loop we can also use it to combine variable variables to iterate through a series of repetitive form fields eg. name1, name2 and name3.

For example:

[source:php]for ($i=1; $i < $num_fields; $i++) {
$temp = "name".$i;
print $$temp."
";
}
[/source]

As you can see you create a dynamic variable name using the value of $i (1, 2, 3 etc) and then save this string in the variable $temp. Therefore on the first iteration $temp contains "name1". To get this to display the content of $name1 you need to use two dollar signs to get the variable variable ie. $$temp. This is very handy when you do not know how many text boxes may be coming from a form, such as in an ecommerce shopping basket. This way if each box has a generic name plus a number on the end which increments each time, it is easy to pass through the count of fields from the form page (which is then stored as $num_fields) and then it can display the code. Plus imagine having 20 text boxes. Compare 20 lines of code to just 4!

Additional Note: To access the form fields you would use slightly different code as below

[source:php]for ($i=1; $i < $num_fields; $i++) {
print $_POST['name'.$i]."
";
}
[/source]

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