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Contents
defmodule Matrix do
defstruct matrix: nil, transposed_matrix: nil
@doc """
Convert an `input` string, with rows separated by newlines and values
separated by single spaces, into a `Matrix` struct.
"""
@spec from_string(input :: String.t()) :: %Matrix{}
def from_string(input) do
rows = input
|> String.split("\n", trim: true)
|> Enum.map(&parse_line/1)
%Matrix{
matrix: rows,
transposed_matrix: rows |> List.zip |> Enum.map(&Tuple.to_list/1)
}
end
defp parse_line(input_line) do
input_line
|> String.split(" ", trim: true)
|> Enum.map(&String.to_integer/1)
end
@doc """
Write the `matrix` out as a string, with rows separated by newlines and
values separated by single spaces.
"""
@spec to_string(matrix :: %Matrix{}) :: String.t()
def to_string(%Matrix{ matrix: rows }) do
rows
|> Enum.map(&join_row/1)
|> Enum.join("\n")
end
defp join_row(row), do: Enum.join(row, " ")
@doc """
Given a `matrix`, return its rows as a list of lists of integers.
"""
@spec rows(matrix :: %Matrix{}) :: list(list(integer))
def rows(%Matrix{matrix: rows}), do: rows
@doc """
Given a `matrix` and `index`, return the row at `index`.
"""
@spec row(matrix :: %Matrix{}, index :: integer) :: list(integer)
def row(%Matrix{matrix: rows}, index), do: Enum.at(rows, index)
@doc """
Given a `matrix`, return its columns as a list of lists of integers.
"""
@spec columns(matrix :: %Matrix{}) :: list(list(integer))
def columns(%Matrix{transposed_matrix: cols}), do: cols
@doc """
Given a `matrix` and `index`, return the column at `index`.
"""
@spec column(matrix :: %Matrix{}, index :: integer) :: list(integer)
def column(%Matrix{transposed_matrix: cols}, index), do: Enum.at(cols, index)
end
Version data entries
170 entries across 170 versions & 1 rubygems