Example Elixir application that
- Parses a CSV file
- Run an application as a CLI app
- Accepts command line args and responds accordingly
If available in Hex, the package can be installed
by adding address_book to your list of dependencies in mix.exs:
def deps do
[
{:address_book, "~> 0.1.0"}
]
endDocumentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/address_book.
mix deps.get
mix escript.build
./address_book --file people.csv --find total
./address_book --file people.csv --find oldest
./address_book --file people.csv --find name --city Melbourne
./address_book --file people.csv --find city --name Tom
This uses CSV
https://github.com/beatrichartz/csvhttps://hexdocs.pm/csv/CSV.html
However there is another lib written that could be used (Nimble CSV) - https://github.com/plataformatec/nimble_csv
Notes while working things out
Lambda
results ="people.csv" |> Path.expand(__DIR__) |> File.stream! |> CSV.decode |> Enum.map(fn(x) -> elem(x, 1) end)
[["Judy", "20", "Sydney"], ["Amy", "43", "Melbourne"], ["Mark", "23", "London"],
["Tom", "71", "Paris"], ["Lily", "65", "Berlin"]]
results ="people.csv" |> Path.expand(__DIR__) |> File.stream! |> CSV.decode |> Enum.map(&(elem(&1, 1)))
[["Judy", "20", "Sydney"], ["Amy", "43", "Melbourne"], ["Mark", "23", "London"],
["Tom", "71", "Paris"], ["Lily", "65", "Berlin"]]
Sorting an Enum of Maps
iex(11)> a = [%{name: 'c', val: 3}, %{name: 'a', val: 1}, %{name: 'z', val: 26}]
[%{name: 'c', val: 3}, %{name: 'a', val: 1}, %{name: 'z', val: 26}]
iex(12)> Enum.sort_by(a, fn(x) -> Map.get(x, :val) end)
[%{name: 'a', val: 1}, %{name: 'c', val: 3}, %{name: 'z', val: 26}]
Calculating the oldest:
An alternative could be looping through the Enum, and comparing with the current largest number "oldest", updating the temporary variable that is "oldest"
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