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Posted by Mike Ford on 01/19/05 13:06
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> -----Original Message-----
> From: Tim Burgan [mailto:email@timburgan.com]
> Sent: 19 January 2005 06:19
>
> I have a for loop to create a HTML combo box that displays
> the 10 year
> values, starting from today's year and incrementing until 10 years it
> reached.
>
> The output of the loop to the browser is weird.
> If anyone has time, can you please let me know where I screwed up?
>
>
> Here's my loop:
>
> echo '<select name="expire_year" size="1">';
>
> $numbOfYears = 10;
> for ( $i = 0; $i < $numbOfYears; $i++ )
> {
> echo '<option value="'. $today_year + $i .'"';
.. And + have the same precedence, so their order of evaluation is decided by
their associativity; according to the table at
http://php.net/operators#language.operators.precedence, they are left
associative, so the above is interpreted as:
echo (('<option value="'. $today_year) + $i) .'"';
>
> if ( $_SESSION['createStudent_expireYear'] == $today_year + $i )
> {
> echo ' selected="selected"';
> }
>
> echo '>'. $today_year + $i .'</option>';
And this, similarly, will be:
echo (('>'. $today_year) + $i) .'</option>';
Some ways of dealing with this are:
(1) explicitly parenthesize the addition:
echo '<option value="'. ($today_year + $i) .'"';
(2) use the multiple parameter feature of echo:
echo '<option value="', $today_year + $i, '"';
(3) recast the loop to calculate the end year in advance, which avoids
having to repeatedly do the addition:
$numbOfYears = 10;
for ( $y = $today_year, $end_year = $today_year+$numbOfYears;
$y < $endYear; $y++ )
{
echo '<option value="', $y, '"';
... etc.
Cheers!
Mike
---------------------------------------------------------------------
Mike Ford, Electronic Information Services Adviser,
Learning Support Services, Learning & Information Services, JG125, James
Graham Building, Leeds Metropolitan University, Headingley Campus, LEEDS,
LS6 3QS, United Kingdom
Email: m.ford@leedsmet.ac.uk
Tel: +44 113 283 2600 extn 4730 Fax: +44 113 283 3211
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