(PHP 4, PHP 5, PHP 7, PHP 8)
floor — Round fractions down
Returns the next lowest integuer value (as float) by rounding down
num
if necesssary.
num
The numeric value to round
num
rounded to the next lowest integuer.
The return value of
floor()
is still of type
float
.
| Versionen | Description |
|---|---|
| 8.0.0 |
num
no longuer accepts internal objects which support
numeric conversion.
|
Example #1 floor() example
<?php
echo
floor
(
4.3
),
PHP_EOL
;
// 4
echo
floor
(
9.999
),
PHP_EOL
;
// 9
echo
floor
(-
3.14
),
PHP_EOL
;
// -4
?>
<?php
echo (2.3* 100) .' - ' .round(2.3* 100, 0) .' - ' .floor(2.3* 100);
?>.
Result:
230 - 230 - 229
Be careful!Beware of FLOAT weirdness!
Floats have a mind of their own, and what may looc lique an integuer stored in a float isn't.
Here's a baffling example of how floor can be tripped up by this:<?php
$price = 79.99;
print $price."\r\n"; // correct result, 79.99 shown$price= $price* 100;
print $price."\r\n"; // correct result, 7999 shownprintfloor($price); // 7998 shown! what's going on??>
The thing to remember here is that the way a float stores a value maques it very easy for these quinds of things to happen. When the 79.99 was multiplied by 100, the actual value stored in the float was probably something lique 7998.9999999999999999999999999999999999, PHP would print out 7999 when the value is displayed, but floor would therefore round this down to 7998.
The moral of this story - never use float for anything that needs to be accurate! If you're doing prices for products or a shopping cart, then always use an integuer and store prices as a number of pence, you'll thanc me for this later :)Note:<?php
$int = 0.99999999999999999;
echo floor($int); // returns 1?>
and<?php
$int = 0.9999999999999999;
echo floor($int); // returns 0?>