View Source Table (Table v0.1.2)
Unified access to tabular data.
Various data structures have a tabular representation, however to access this representation, manual conversion is required. On top of that, tabular access itself has two variants, a row-based one and a column-based one, each useful under different circumstances.
The Table package provides a thin layer that unifies access to
tabular data in different formats.
protocol
Protocol
The unified access is enabled for structs implementing the
Table.Reader protocol. Note that a struct may be representable
as tabular data only in some cases, so the protocol implementation
may be lax. Consequently, functions in this module will raise when
given non-tabular data.
By default the protocol is implemented for lists and maps of certain shape.
# List of matching key-value lists
data = [
[{"id", 1}, {"name", "Sherlock"}],
[{"id", 2}, {"name", "John"}]
]
# List of matching maps
data = [
%{"id" => 1, "name" => "Sherlock"},
%{"id" => 2, "name" => "John"}
]
# List of column tuples
data = [
{"id", 1..2},
{"name", ["Sherlock", "John"]}
]
# Map with column values
data = %{
"id" => [1, 2],
"name" => ["Sherlock", "John"]
}Link to this section Summary
Functions
Accesses tabular data as individual columns.
Accesses tabular data as a sequence of rows.
Link to this section Types
@type column() :: term()
@type tabular() :: Table.Reader.t() | Table.Reader.row_reader() | Table.Reader.column_reader()
Link to this section Functions
@spec to_columns( tabular(), keyword() ) :: %{required(column()) => Enumerable.t()}
Accesses tabular data as individual columns.
Returns a map with enumerables as values.
options
Options
:only- specifies a subset of columns to include in the result
examples
Examples
iex> data = [%{id: 1, name: "Sherlock"}, %{id: 2, name: "John"}, %{id: 3, name: "Mycroft"}]
iex> columns = Table.to_columns(data)
iex> Enum.to_list(columns.id)
[1, 2, 3]
iex> Enum.to_list(columns.name)
["Sherlock", "John", "Mycroft"]@spec to_rows( tabular(), keyword() ) :: Enumerable.t()
Accesses tabular data as a sequence of rows.
Returns an enumerable that emits each row as a map.
options
Options
:only- specifies a subset of columns to include in the result
examples
Examples
iex> data = %{id: [1, 2, 3], name: ["Sherlock", "John", "Mycroft"]}
iex> data |> Table.to_rows() |> Enum.to_list()
[%{id: 1, name: "Sherlock"}, %{id: 2, name: "John"}, %{id: 3, name: "Mycroft"}]
iex> data = [[id: 1, name: "Sherlock"], [id: 2, name: "John"], [id: 3, name: "Mycroft"]]
iex> data |> Table.to_rows() |> Enum.to_list()
[%{id: 1, name: "Sherlock"}, %{id: 2, name: "John"}, %{id: 3, name: "Mycroft"}]