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Perl Predefined Numeric Functions

Commonly Used Perl Predefined Functions Part 2

Perl Course

Foreword: In this part of the series, I talk about Perl Predefined Numeric Functions that are commonly used.

By: Chrysanthus Date Published: 19 Oct 2015

Introduction

This is part 2 of my series, Commonly Used Perl Predefined Functions. In this part of the series, I talk about Perl Predefined Numeric Functions that are commonly used. You should have read the previous part of the series before reaching here, as this is a continuation.

The rand() Function
The syntaxes of the rand function are:

    rand EXPR
    rand

EXPR is the argument, a number. If EXPR is omitted, the value of 1 is used. This function returns a random number greater than or equal to 0, and less than the value of EXPR. The random number may have a fraction (decimal part). Try the following code:

use strict;

    my $var = rand(10);
    print $var;

I tried it and I had,

    2.2564697265625

If you tried the code, you would have a different number.

Now, note that the random number returned is not 100% random. It may be predicted. So it is not 100% secured. If you want a random number, which is hopefully secured, go to any of the following pages:  http://search.cpan.org/perldoc/Data::Entropy, http://search.cpan.org/perldoc/Crypt::Random, http://search.cpan.org/perldoc/Math::TrulyRandom

The abs() Function
The syntaxes of this function are:

    abs VALUE
    abs

The argument is VALUE. If VALUE is absent, the value of $_ is used. This function will return a whole number from a signed number. Try the following code:

use strict;

    my $val  = abs(-5);
    print $val;

The output is 5.

The int() Function
An integer is a whole number, which may be positive or negative. This function truncates a float (real) number and returns the integer part. That is, it throws away the decimal (fractional) part of a number and returns the integer part. It does not round the number. Try the following code:

use strict;

    my $val  = int(16.87);
    print $val;

The output is 16.

The sqrt() function
This function returns the square root of a number. The syntaxes are:

    sqrt EXPR
    sqrt

EXPR is a number. If EXPR is omitted, the value of $_ is used (corresponding to the second syntax). Try the following code:

use strict;

    my $val  = sqrt(100);
    print $val;

The output is, 10.

The hex() Function
This is the same function we saw in the previous part of the series. The syntaxes are:

    hex EXPR
    hex

EXPR is typically a string (single or double quotes) of hexadecimal digits. Hexadecimal digits are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f . This function converts a string of hexadecimal digits to the corresponding decimal (base 10) number. A string of hexadecimal digits is a hexadecimal number delimited by quotes. If EXPR is omitted, the value of $_ is used. Try the following code:

use strict;

    my $val  = hex('ff');
    print $val;

The output is 255.

That is it for this part of the series. We stop here and continue in the next part.

Chrys

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