README.md

Raku Data::TypeSystem

This Raku package provides a type system for different data structures that are coercible to full arrays. Its code was originally developed in "Data::Reshapers", [AAp1].

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Installation

From Zef ecosystem:

zef install Data::TypeSystem

From GitHub:

zef install https://github.com/antononcube/Raku-Data-TypeSystem.git

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Usage examples

The type system conventions follow those of Mathematica's Dataset -- see the presentation "Dataset improvements".

Here we get the Titanic dataset, change the "passengerAge" column values to be numeric, and show dataset's dimensions:

use Data::ExampleDatasets;
my $url = 'https://raw.githubusercontent.com/antononcube/Raku-Data-Reshapers/main/resources/dfTitanic.csv';
my @dsTitanic = example-dataset($url, headers => 'auto');
@dsTitanic = @dsTitanic.map({$_<passengerAge> = $_<passengerAge>.Numeric; $_}).Array;
@dsTitanic.elems

# 1309

Here is a sample of dataset's records:

.say for @dsTitanic.pick(5)

# {id => 1097, passengerAge => 0, passengerClass => 3rd, passengerSex => male, passengerSurvival => died}
# {id => 1018, passengerAge => 20, passengerClass => 3rd, passengerSex => male, passengerSurvival => survived}
# {id => 31, passengerAge => 40, passengerClass => 1st, passengerSex => male, passengerSurvival => died}
# {id => 1030, passengerAge => -1, passengerClass => 3rd, passengerSex => male, passengerSurvival => died}
# {id => 126, passengerAge => -1, passengerClass => 1st, passengerSex => male, passengerSurvival => died}

Here is the type of a single record:

use Data::TypeSystem;
deduce-type(@dsTitanic[12])

# Struct([id, passengerAge, passengerClass, passengerSex, passengerSurvival], [Int, Int, Str, Str, Str])

Here is the type of single record's values:

deduce-type(@dsTitanic[12].values.List)

# Tuple([Atom((Int)), Atom((Str)), Atom((Str)), Atom((Str)), Atom((Int))])

Here is the type of the whole dataset:

deduce-type(@dsTitanic)

# Vector(Struct([id, passengerAge, passengerClass, passengerSex, passengerSurvival], [Int, Int, Str, Str, Str]), 1309)

Here is the type of "values only" records:

my @valArr = @dsTitanic>>.values>>.Array;
deduce-type(@valArr)

# Vector((Any), 1309)

Here is the type of the string values only records:

my @valArr = @dsTitanic.map({ $_.grep({ $_.value ~~ Str }).Hash })>>.values>>.Array;
.say for @valArr.pick(4);

# [1st male died]
# [3rd male died]
# [male died 3rd]
# [died 3rd male]

deduce-type(@valArr);

# Vector(Vector(Atom((Str)), 3), 1309)

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References

[AAp1] Anton Antonov, Data::Reshapers Raku package, (2021), GitHub/antononcube.