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Home: Perl Programming Help: Frequently Asked Questions:
Does perl have a round function? What about ceil()

 



Jasmine
Administrator

Jan 19, 2001, 2:32 PM

Post #1 of 1 (2617 views)
Does perl have a round function? What about ceil() Can't Post

(From the Perl FAQ)

Does perl have a round function? What about ceil() and floor()? Trig functions?

Remember that int() merely truncates toward 0. For rounding to a certain number of digits, sprintf() or printf() is usually the easiest route.

Code
    printf("%.3f", 3.1415926535);       # prints 3.142

The POSIX module (part of the standard perl distribution) implements ceil(), floor(), and a number of other mathematical and trigonometric functions.

Code
    use POSIX; 
$ceil = ceil(3.5); # 4
$floor = floor(3.5); # 3

In 5.000 to 5.003 Perls, trigonometry was done in the Math::Complex module. With 5.004, the Math::Trig module (part of the standard perl distribution) implements the trigonometric functions. Internally it uses the Math::Complex module and some functions can break out from the real axis into the complex plane, for example the inverse sine of 2.

Rounding in financial applications can have serious implications, and the rounding method used should be specified precisely. In these cases, it probably pays not to trust whichever system rounding is being used by Perl, but to instead implement the rounding function you need yourself.



 
 


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