Membrane v0.1.0 Membrane View Source
Membrane provides a wrapper for filtering data with simplicity and efficiently. It filters out list of structs or maps that satisfies the query. The Query is inspired by Mongo, hence there’s a lot of similarities.
Installation
Make sure elixir >= 1.6, then add following line to your mix.exs file
def deps do
...
{:membrane, "~> 0.1.0"}
end Run mix deps.get to install the package
Query
The examples below cover queries on exact, lesser than, greater than and nested comparision .
To get in depth idea on query parameters that the module supports, please visit
Membrane.Query module.
Examples
In the examples below, list of maps are used; But it can be list of structs or mix of both structs and maps.
iex> data = [
...> %{id: 1, name: "Bob", action: "talk", age: 30},
...> %{id: 3, name: "Helen", action: "talk", age: 30},
...> %{id: 1, name: "Rocky", action: "bark", age: 10},
...> %{id: 3, name: "Rocky", action: "meow", age: 6},
...> %{id: 10, age: 3},
...> %{id: 1, type: "car", age: 12}
...> ]
[
%{action: "talk", age: 30, id: 1, name: "Bob"},
%{action: "talk", age: 30, id: 3, name: "Helen"},
%{action: "bark", age: 10, id: 1, name: "Rocky"},
%{action: "meow", age: 6, id: 3, name: "Rocky"},
%{age: 3, id: 10},
%{age: 12, id: 1, type: "car"}
]
## Filters data with id = 1
iex> Membrane.filter(data, id: 1)
[
%{age: 12, id: 1, type: "car"},
%{action: "bark", age: 10, id: 1, name: "Rocky"},
%{action: "talk", age: 30, id: 1, name: "Bob"}
]
## Filters data with id > 1 and has :action attribute
iex> Membrane.filter(data, id: [gt: 1], action: :exists)
[
%{action: "meow", age: 6, id: 3, name: "Rocky"},
%{action: "talk", age: 30, id: 3, name: "Helen"}
]The module also supports nested structs.
Examples
iex> data = [
...> %{id: 1, name: "Bob", action: "talk", data: %{age: 30, country: "USA"} },
...> %{id: 3, name: "Helen", action: "talk", data: %{age: 26, country: "USA"}},
...> %{id: 3, name: "William", action: "talk", data: %{age: 32, country: "France"}},
...> %{id: 1, name: "Rocky", action: "bark", age: 10},
...> ]
[
%{id: 1, name: "Bob", action: "talk", data: %{age: 30, country: "USA"} },
%{id: 3, name: "Helen", action: "talk", data: %{age: 26, country: "USA"}},
%{id: 3, name: "William", action: "talk", data: %{age: 32, country: "France"}},
%{id: 1, name: "Rocky", action: "bark", age: 10},
]
## Filters data with action = "talk" and age attribute in data >= 30
iex> Membrane.filter(data, action: "talk", data: [age: [gte: 30]])
[
%{id: 3, name: "William", action: "talk", data: %{age: 32, country: "France"}},
%{id: 1, name: "Bob", action: "talk", data: %{age: 30, country: "USA"} }
]Link to this section Summary
Functions
This method filters the data that satisfies the query. It takes in two arguments data
and query. The results will be in reverse order
Link to this section Functions
This method filters the data that satisfies the query. It takes in two arguments data
and query. The results will be in reverse order.
By default the option is :default, you can pass :negate to negate the filtered data.
Examples
iex> data = [%{a: 1, b: 2, c: 3}, %{a: 2, b: 3, c: -1}, %{a: 1, b: -3, c: 5}]
iex> Membrane.filter(data, [a: 1])
[%{a: 1, b: -3, c: 5}, %{a: 1, b: 2, c: 3}]
iex> Membrane.filter(data, [b: [gt: 1], c: [lte: 3]])
[%{a: 2, b: 3, c: -1}, %{a: 1, b: 2, c: 3}]
# As the argument is keyword list, the brackets can be dropped
iex> Membrane.filter(data, b: [gt: 1], c: [lte: 3])
[%{a: 2, b: 3, c: -1}, %{a: 1, b: 2, c: 3}]
# To negate the data, add :negate as the third argument
iex> Membrane.filter(data,[a: [lt: 2]], :negate)
[%{a: 2, b: 3, c: -1}]