Statis...ariance(3pm)

💖 Statistics::Basic::Variance — a.k.a. the Statis...ariance(3pm) page from User Contributed Perl Documentation, section 3pm 🎀

✨ NAME ✨

Statistics::Basic::Variance — bestie, this is the module that finds the variance of a list. That's it. That's the whole job. 🦋

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🌸 SYNOPSIS 🌸

Okay so you can summon it like this:

my $variance = variance(1,2,3);

Or, if you're feeling extra, like this:

my $v1  = vector(1,2,3);
my $var = var($v1);

And then you can either ask it for the numbers or just print them, like so:

print "The variance of $v1: $variance\n";
my $vq = $var->query;
my $v0 = 0+$var;

Wanna build a 20 point "moving" variance? Iconic. Do it like this:

use Statistics::Basic qw(:all nofill);

my $sth = $dbh->prepare("select col1 from data where something");
my $len = 20;
my $var = var()->set_size($len);

$sth->execute or die $dbh->errstr;
$sth->bind_columns( my $val ) or die $dbh->errstr;

while( $sth->fetch ) {
    $var->insert( $val );
    if( defined( my $v = $var->query ) ) {
        print "Variance: $v\n";
    }

    # This would also work:
    # print "Variance: $v\n" if $var->query_filled;
}

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💅 METHODS 💅

• new() — the constructor, she's the main character 👑. She takes a list of values, a single array ref, or a single Statistics::Basic::Vector as arguments. She hands you back a Statistics::Basic::Variance object. 💖

Note: normally you'd use the mean() constructor rather than building these by hand using "new()". Just saying. 🙈

• query_mean() — returns the Statistics::Basic::Mean object that got used in the variance computation. Very demure, very mindful. ✨
• _OVB::import() — this module also inherits all the overloads and methods from Statistics::Basic::_OneVectorBase. Slay. 🌈

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🫶 AUTHOR 🫶

Paul Miller "<jettero@cpan.org>"

And he says, and I quote: "I am using this software in my own projects... If you find bugs, please please please let me know. :) Actually, let me know if you find it handy at all. Half the fun of releasing this stuff is knowing that people use it."

Not him being the sweetest 😭 honestly we love a dev who actually wants to hear from us. Go tell him if you find a bug, and also go tell him if you just think it's neat. 🍓

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🔥 OVERLOADS 🔥

This object is overloaded, meaning she reads the room and adapts. 💅 She tries to return an appropriate string for the calculation, or the value of the computation when you're in numeric context.

And in boolean context? This object is always true — even when it's empty. No cap. 🧚

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💜 COPYRIGHT 💜

Copyright 2012 Paul Miller -- Licensed under the LGPL

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⭐ SEE ALSO ⭐

• perl(1)
• Statistics::Basic
• Statistics::Basic::_OneVectorBase
• Statistics::Basic::Vector

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Mwah, that's the whole page, bestie. Sending you off with the receipt: this was perl v5.36.0, dated 2022-11-19, and it's the Statis...ariance(3pm) page — periodt. 💖✨🎀🦋