PHP round, rounding, round function Use example _php instance

Decimal Example:

PHP retains two decimal places and rounded up

Copy Code code as follows:

$n = 0.1265489;
Echo sprintf ("%.2f", $n); 0.13

You can see we used the sprintf function to format the $n%.2f is the target format, where 2 indicates that two-bit f means float (floating-point) 3rd for decimal 6 is rounded
Let's look at an example.

Copy Code code as follows:

$n =0.1265489
Echo substr (sprintf ("%.3", $n), 0,-1);//0.12

The code output is reserved 2 decimal is not rounded, in fact, we understand that the characteristics of the sprintf will be rounded decimal, we retain one more, and then use SUBSTR to intercept the top 2

Take the whole example:

Copy Code code as follows:

Echo ceil (4.1); 5
echo ceil (9.999); 10

Ceil function is to take the whole function up, what is called up? Which means that if you go beyond a little, move on. One example of 4.1 becomes 5.

Contrary to it, there is a function called floor. Let's see how it's used.

Copy Code code as follows:

Echo Floor (4.1); 4
echo Floor (9.999); 9

The characteristic of floor is particularly noticeable in the second output, that is, not giving you as many decimal digits as infinity or nearly 10, or an integer that is not down to 9.

Round function

Copy Code code as follows:

? Php
Echo round (3.4); 3
Echo round (3.5); 4
Echo round (3.6); 4
Echo Round (3.6, 0); 4
Echo Round (1.95583, 2); 1.96
Echo Round (1241757,-3); 1242000
Echo Round (5.045, 2); 5.05
Echo Round (5.055, 2); 5.06
?>

The round function is described in the PHP manual as follows:

Float round (float $val [, int $precision = 0 [, int $mode = php_round_half_up]])
Returns the result of rounding Val according to the specified precision precision (number of digits after the decimal point). Precision can also be negative or 0 (the default value).

The parameter of the

round is a data source, parameter two is the number of decimal places to keep and then one (for example, you enter 2 then the 3rd is the next one) is rounded, when he is a negative number, from the data source the last one began to forward the corresponding length of 0 and the last rounded like round ( 123456,-2) is 123456 from 6 onwards the number two digits become 0, and the last 5 (from the first digit of the forward is 6 the last is 5) rounded, output 123500