Perl Data Analytics Tutorial

Let's find the maximum value

I will explain how to find the maximum value using a Perl program.

Let's find the maximum value of the

array.

Consider an array that contains only positive numbers (> 0), such as:

@array = (1, 8, 3, 5, 7);

Sample program to find the maximum value of an array

Actually find the maximum value from the array. The List::Util module has a max function, which is not used in this example.

You can find the maximum value by preparing a variable to store the maximum value and comparing it with the elements of the array one by one.

use strict;
use warnings;

my @array = (1, 8, 3, 5, 7); 

my $max = 0;

for my $num (@array) {
  if ($max < $num) {
    $max = $num;
  }
}

print "$max\n";

Execution result

8

I think that the process is very easy to understand by comparing each one.

* To simplify the code, we will handle an array that contains only positive numbers (> 0).

Let's find the maximum value of a specific column from the tabular data.

Consider the following data.

It is as follows when expressed by the reference of the array and the hash.

$array_ref = [
  {name =>'bob', age => 9},
  {name =>'tom', age => 14},
  {name =>'alice', age => 11}
];;

Sample program to find the maximum value of the age column

Data access has become a little more difficult due to the complexity of the referenced data,

The method of checking is the same as before.

use strict;
use warnings;

my $array_ref = [
  {name => 'bob', age => 9},
  {name => 'tom', age => 14},
  {name => 'alice',age => 11}
];

my $max = 0;

for my $info (@{$array_ref}) {
  if ($max < $info->{'age'}) {
    $max = $info->{'age'};
  }
}

print "$max\n";

Execution result

14

The process is the same as before except that the reference is dealt with.

You can copy and paste this program and try it immediately at PerlBanjo.