[PHP] Weird results of "=="
Hello
I have the following code:
($b + $c))
{
// do the second thing
}
elseif ($a < ($b + $c))
{
// do the third thing
}
?>
Each of the three variables is derived by some earlier calculation, but for
testing purposes I have made sure that they end up being $a = $b and $c = 0.
I have tested for three different values (of $a) and gotten all three
results. That is, once the first block has executed, once the second block
and once the third block.
Am I missing something really obvious here?
How do I execute only the first block if indeed $a == ($b + $c) ?
Thank you for your help.
Brian
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Re: [PHP] Weird results of "=="
That did the trick.
Thanks a million.
Brian
"Jasper Bryant-Greene" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Brian P. O'Donnell wrote:
> > >
> > $a = 252.73;
> > $b = 252.73;
> > $c = 0;
> >
> > if ($a == ($b + $c))
> > {
> > // do the first thing
> > }
> > elseif ($a > ($b + $c))
> > {
> > // do the second thing
> > }
> > elseif ($a < ($b + $c))
> > {
> > // do the third thing
> > }
> >
> > ?>
> >
> > Each of the three variables is derived by some earlier calculation, but
for
> > testing purposes I have made sure that they end up being $a = $b and $c
= 0.
> > I have tested for three different values (of $a) and gotten all three
> > results. That is, once the first block has executed, once the second
block
> > and once the third block.
> >
> > Am I missing something really obvious here?
>
> This is an inherent problem with floating-point operations, especially
> comparison, and is not unique to PHP. Often numbers will be off by some
> miniscule amount, just enough to make them not equal.
>
> What I would do in this situation is create a function float_equals(),
> after deciding what delta is acceptable for your situation, like this:
>
> define('MAX_FLOAT_DELTA', 0.001); // Or whatever is acceptable for you
>
> function float_equals($a, $b) {
> return (abs($a - $b) <= MAX_FLOAT_DELTA);
> }
>
> Then use float_equals($x, $y) instead of $x == $y.
>
> Jasper
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Re: [PHP]
It's bad enough when somebody posts a blank email to the list, but when people start posting blank replies, it gets really frustrating. Please cease & desist. Thanks Brian "Andy Pieters" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Re: Saturdays and Sundays
""Shaun"" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Hi,
>
> Is it possible to get the number of saturdays and sundays for a given
month
> / year?
>
> Thanks for your help.
Here's another way to do it. Each function will return either 4 or 5. If you
need both Saturdays and Sundays, just call both functions:
3) {
$sat++;
}
break;
case 2:
if ((date("L", $first_day) == 1) && (date("w", $first_day) > 5)) {
$sat++;
}
break;
case 4:
case 6:
case 9:
case 11:
if (date("w", $first_day) > 4) {
$sat++;
}
break;
}
return($sat);
}
function get_sundays($month, $year) {
$sun = 4;
// time stamp of noon on the last day of the month
$last_day = mktime(12, 0, 0, $month, date("t", $first_day), $year);
switch ($month) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:
if (date("w", $last_day) < 3) {
$sat++;
}
break;
case 2:
if ((date("L", $last_day) == 1) && (date("w", $last_day) < 1)) {
$sat++;
}
break;
case 4:
case 6:
case 9:
case 11:
if (date("w", $last_day) < 2) {
$sat++;
}
break;
}
return($sun);
}
?>
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[PHP] Re: Saturdays and Sundays
Sorry, I made a mistake. See below:
""Brian P. O'Donnell"" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
>
> ""Shaun"" <[EMAIL PROTECTED]> wrote in message
> news:[EMAIL PROTECTED]
> > Hi,
> >
> > Is it possible to get the number of saturdays and sundays for a given
> month
> > / year?
> >
> > Thanks for your help.
>
> Here's another way to do it. Each function will return either 4 or 5. If
you
> need both Saturdays and Sundays, just call both functions:
>
>
> function get_saturdays($month, $year) {
>
> $sat = 4;
>
> // time stamp of noon on the first day of the month
> $first_day = mktime(12, 0, 0, $month, 1, $year);
>
> switch ($month) {
> case 1:
> case 3:
> case 5:
> case 7:
> case 8:
> case 10:
> case 12:
> if (date("w", $first_day) > 3) {
> $sat++;
> }
> break;
> case 2:
> if ((date("L", $first_day) == 1) && (date("w", $first_day) > 5)) {
> $sat++;
> }
> break;
> case 4:
> case 6:
> case 9:
> case 11:
> if (date("w", $first_day) > 4) {
> $sat++;
> }
> break;
> }
>
> return($sat);
>
> }
>
> function get_sundays($month, $year) {
>
> $sun = 4;
>
> // time stamp of noon on the last day of the month
The following line referenced a variable in the other function. DUH!
It should be:
$last_day = mktime(12, 0, 0, $month, date("t", mktime(12, 0, 0, $month,
1, $year)), $year);
>
> switch ($month) {
> case 1:
> case 3:
> case 5:
> case 7:
> case 8:
> case 10:
> case 12:
> if (date("w", $last_day) < 3) {
> $sat++;
> }
> break;
> case 2:
> if ((date("L", $last_day) == 1) && (date("w", $last_day) < 1)) {
> $sat++;
> }
> break;
> case 4:
> case 6:
> case 9:
> case 11:
> if (date("w", $last_day) < 2) {
> $sat++;
> }
> break;
> }
>
> return($sun);
>
> }
>
> ?>
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Re: [PHP] Integer - boundary?
""Gustav Wiberg"" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > > - Original Message - > From: "Shaw, Chris - Accenture" <[EMAIL PROTECTED]> > To: "Gustav Wiberg" <[EMAIL PROTECTED]>; "PHP General" > > Sent: Wednesday, September 07, 2005 5:03 PM > Subject: RE: [PHP] Integer - boundary? > > > > > -Original Message- > > From: Gustav Wiberg [mailto:[EMAIL PROTECTED] > > > > > Hi there! > > > > > What is the boundary for an integer? > > > > > seems to be a easy question, but I can't find it... > > > > > > /G > > http://www.varupiraten.se/ > > > > > According to the manual, > > > "The size of an integer is platform-dependent, although a maximum value of > about two billion is the usual value (that's 32 bits signed). PHP does not > support unsigned integers." > > > > > > This message has been delivered to the Internet by the Revenue Internet > e-mail service > > * > > > -- > No virus found in this incoming message. > Checked by AVG Anti-Virus. > Version: 7.0.344 / Virus Database: 267.10.18/91 - Release Date: 2005-09-06 > > Hi there! > > Thanx! > > Hm... I would rephrase my question.. Is it possible to get the maximum > integer-value that can be used? > Hi Try this code to see what it is on your platform: Brian -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Integer - boundary?
""M. Sokolewicz"" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > or, easier, simply make this script: > echo PHP_INT_MAX; > ?> > > and you're done :P The maximum integer value is stored in PHP_INT_MAX as > of 4.4.0 and PHP 5.0.5 > > before that, you had to use a way as the one Brian posted Ahhh, I see. I am running 4.3.9 Thanks; I'll know that when I upgrade. Brian -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Re: mktime
"Dan Brow" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> A little confused with mktime, I'm trying to get how many days are in a
> year.
>
> $year = "2006";
> $epoch = mktime(0, 0, 0, 1, 0, $year); // I have to have 1 for month or
> I get which day it is now. Which sucks.
> $date = date("z Y", $epoch);
> print($date); // here is the problem, I get 365 days, but the year is
> 2005, not 2006, same goes for any year I put in.
>
> What am I doing wrong?
January 0th is December 31st last year
Brian
>
> Thanks,
> Dan.
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Re: [PHP] mktime
"Jasper Bryant-Greene" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Dan Brow wrote:
> > A little confused with mktime, I'm trying to get how many days are in a
> > year.
>
> How about doing it differently. I'd tackle this problem like this:
>
> $year = '2005';
> $time = strtotime("1 January $year");
> $isLeapYear = date('L', $time);
>
> if($isLeapYear == '1') {
> $days = 366;
> } else {
> $days = 365;
> }
> ?>
I'd shorten it up even more:
Brian
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