dynamically adding leading zero

mystrymaster

alright so I have this

<?php  $xx = 01;
  WHILE ($xx <= 31) {
       echo "<option value='$xx'>$xx</option>";
       $xx++;
} ?>

now the result is

1
2
3
4
etc

how do I get the results to be ?
01
02
03
04
etc

willmullis

may I ask why exactly you want this.

kevinsequeira

use str_pad

http://ca2.php.net/manual/en/function.str-pad.php

i guess he wants it cause in the drop down box he wants the values to be 01 and not 1

reg
kevin

cgraz

I'd firstly clean that up by using a for loop instead of a while loop. For loops were developed to do what you are using this while loop to do. I can't remember off of the top of my head if there is a function to add on leading zeros, so a simple if statement will do

for($i=1; $i <31; $i++) { 

   if(strlen($i) < 2) {
       echo "0" . $i . "<br>";
   } else {
       echo $i . "<br>";
   }

}

Cgraz

kevinsequeira

here u go

  $xx = 01;
  WHILE ($xx <= 31) {
			$xx = str_pad($xx, 2, "0", STR_PAD_LEFT);
		  echo "<option value='$xx'>$xx</option>";
    $xx++;
		}

reg
kevin

mystrymaster

Alright so to me the for and while loop are doing the same thing in this instance.
So what would be the difference?

Is For quicker then while? or vice versa?

Thanks for all the help

And yes I would like the leading zeros for a drop down as I think it looks better

HalfaBee

If you want to add leading zeros you can use printf( '%02d',$xx );

As for the while() loops they are a poor mans for() loop.

HalfaBee

BeastRider

Use formatted print to string (sprintf) or formatted print (printf)

http://us4.php.net/manual/en/function.sprintf.php

mystrymaster

halfabee - why is that? what are the differences in them?

HalfaBee

I just find it ridiculous to use 3 extra lines of code in a while loop when that is what a for() loop is designed for.

The for() construct tells you exactly what is happening in 1 line of code.
The while() construct makes you have to look through the whole loop just to work out it is counting from 0-9

Its easy when there is only 1 or 2 lines of code, but if you have 50 lines inside the loop its a pain.

HalfaBee

$i=0;
while( $i<10 )
{
echo $i;
$i++;
}

for( $i=0;$i<10;$i++ )
echo $i

stolzyboy

its generally easier to use for loops and makes more sense when you know how many results you want or need, but when you have an unexpected results number, a while loop is the way to go, as in getting a results array, it is much easier to use a while loop than a for loop, IMHO

BeastRider

WHILE is most useful when you want to be able to control the increment amount inside the loop (such as skipping a value). Otherwise, I agree, FOR makes more sense, and I think most compilers do a better job of optimizing FOR statements than WHILE's with a loop increment.