CsvGenerator (CsvGenerator v0.2.0)

This library provides an easy way to generate CSV files. It allows you to define the colums and their respective types.

Example

defmodule MyCSV do
  use CsvGenerator

  column :name, :string
  column :joined, :date, format: "%d-%m-%Y"
  column :points, :integer, label: "points earned"
  hardcoded :string, "Game", "domino"
end

You would then render the CSV bij calling the render/1 method with the list of lines to render.

Example

iex> MyCSV.render([ 
   %{ name: "Chris McCord", joined: ~D[2020-01-01], points: 110},
   %{ name: "Jose Valim", joined: ~D[2020-03-29], points: 10} ])
"\"name\",\"joined\",\"points earned\",\"Game\"\n\"Chris McCord\",01-01-2020,110,\"domino\"\n\"Jose Valim\",29-03-2020,10,\"domino\""

By default the CSV columns will be seperated by a ",", the lines by a "\n". This can be changed by using delimiter and line_ending.

Example

defmodule MyCSV do
  use CsvGenerator

  delimiter ";"
  line_ending "\r\n"

  column :name, :string
  column :birthday, :date, format: "%d-%m-%Y"
  column :points, :integer
end

iex> MyCSV.render([ 
   %{ name: "Jose Valim", joined: ~D[2020-03-29], points: 10} ])
"\"name\";\"joined\";\"points earned\"\n\"Jose Valim\";29-03-2020;10"

Formatting

A formatter is included, to be able to have mix format use it, you have to add it to your own .formatter.exs in import_deps.

Example

[
  import_deps: [:ecto, :phoenix, :csv_generator],
  inputs: ["*.{ex,exs}", "priv/*/seeds.exs", "{config,lib,test}/**/*.{ex,exs}"],
  subdirectories: ["priv/*/migrations"]
]

Summary

Functions

column(name, type, opts \\ [])

Defines a column in the CSV.

decimal_point(char)

Specify the decimal point, default: "."

delimiter(char)

Specify the character to use as column delimiter, default: ","

hardcoded(type, header, value)

Defines a column in the CSV that will always have the same hardcoded value.

header(flag)

Add the header to the generated CSV, default: true.

line_ending(char)

Specify the line ending to use, default: "\n".

Functions

column(name, type, opts \\ [])

(macro)

Defines a column in the CSV.

column name, type, options

The column name will be used to select the value from the given input.

The following types are currently supported:

Type	Elixir type	Default format
`:string`	`String`	n/a
`:integer`	`Integer`	n/a
`:float`	`Float`	n/a
`:date`	`Date`	`"%Y-%m-%d"`
`:time`	`DateTime` or `Integer`	`"%H:%M"`
`:datetime`	`DateTime`	`"%Y-%m-%d %H:%M:%S"`

For :date, :time, and :datetime, any of the Date(Time) types that are compatible with Calendar.strftime/2 are allowed. :time also allows an Integer value that represents the time within a day.

Options

:header - Use this instead of the name for column header.
:format - Supply a different format string, see Calendar.strftime/2.
:digits - Supply the number of digits for a Float.

:with - Specifies a function to be called on the value before processing.

        column :value, :integer, with: &calc/1 or
        column :value, :integer, with: fn(x) -> x * 2 end

:source - Use another field as the source for this column, this allows you to use the same column multiple times.

nil values

Columns with a nil value will be empty in the output. If you do not want this, if you want some default value, then use the with: option to supply a function that transforms the nil into something, formatting and rounding options will be applied.

column :c3po, :integer, with: fn i -> if i == nil, do: 0, else: i end

decimal_point(char)

(macro)

Specify the decimal point, default: "."

Example

decimal_point ","

delimiter(char)

(macro)

Specify the character to use as column delimiter, default: ","

Example

delimiter ";"

hardcoded(type, header, value)

(macro)

Defines a column in the CSV that will always have the same hardcoded value.

Example

hardcoded :string, "name", "John"

For type check out the possibilities in column/3. Make sure the value is of type.

line_ending(char)

(macro)

Specify the line ending to use, default: "\n".

Example

line_ending "\r\n"