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83 changes: 34 additions & 49 deletions lib/shitty_linq_ex.ex
Original file line number Diff line number Diff line change
Expand Up @@ -6,20 +6,14 @@ defmodule ShittyLinqEx do
@doc """
Applies an accumulator function over a sequence. The specified seed value is used as the initial
accumulator value, and the specified function is used to select the result value.

## Parameters

- `source`: an enumerable to aggregate over.
- `seed`: the initial accumulator value.
- `func`: an accumulator function to be invoked on each element.
- `resultSelector`: a function to transform the final accumulator value into the result value.

## Returns

The transformed final accumulator value.

## Examples

iex> import ShittyLinqEx, only: [aggregate: 4]
iex> fruits = ["apple", "mango", "orange", "passionfruit", "grape"]
iex> aggregate(
Expand All @@ -34,7 +28,6 @@ defmodule ShittyLinqEx do
...> end,
...> &String.upcase/1)
"PASSIONFRUIT"

"""
def aggregate(source, seed, func, resultSelector)
when is_list(source) and is_function(func, 2) and is_function(resultSelector, 1) do
Expand Down Expand Up @@ -81,19 +74,13 @@ defmodule ShittyLinqEx do
@doc """
Applies an accumulator function over a sequence.
The specified seed value is used as the initial accumulator value.

## Parameters

- `source`: an enumerable to aggregate over.
- `seed`: the initial accumulator value.
- `func`: an accumulator function to be invoked on each element.

## Returns

The final accumulator value.

## Examples

iex> import ShittyLinqEx, only: [aggregate: 3]
iex> ints = [4, 8, 8, 3, 9, 0, 7, 8, 2]
iex> aggregate(
Expand All @@ -107,23 +94,19 @@ defmodule ShittyLinqEx do
...> end
...> end)
6

iex> import ShittyLinqEx, only: [aggregate: 3]
iex> aggregate(4..1, 1, &*/2)
24

iex> import ShittyLinqEx, only: [aggregate: 3]
iex> aggregate(1..3, 1, &+/2)
7

iex> import ShittyLinqEx, only: [aggregate: 3]
iex> letters_to_numbers = %{a: 1, b: 2, c: 3}
iex> aggregate(
...> letters_to_numbers,
...> [],
...> fn {key, _value}, keys -> [key | keys] end)
[:c, :b, :a]

"""
def aggregate(source, seed, func)
when is_list(source) and is_function(func, 2) do
Expand All @@ -150,26 +133,19 @@ defmodule ShittyLinqEx do

@doc """
Applies an accumulator function over a sequence.

## Parameters

- `source`: an enumerable to aggregate over.
- `func`: an accumulator function to be invoked on each element.

## Returns

The final accumulator value.

## Examples

iex> import ShittyLinqEx, only: [aggregate: 2]
iex> sentence = "the quick brown fox jumps over the lazy dog"
iex> words = String.split(sentence)
iex> aggregate(
...> words,
...> fn word, workingSentence -> word <> " " <> workingSentence end)
"dog lazy the over jumps fox brown quick the"

"""
def aggregate([head | tail], func)
when is_function(func, 2) do
Expand Down Expand Up @@ -208,59 +184,58 @@ defmodule ShittyLinqEx do

@doc """
Inverts the order of the elements in a sequence.

## Parameters

- `list`: A sequence of values to reverse.

## Returns

A sequence whose elements correspond to those of the input sequence in reverse order.

## Examples

iex> import ShittyLinqEx, only: [reverse: 1]
iex> reverse(["A", "B", "C"])
["C", "B", "A"]

iex> import ShittyLinqEx, only: [reverse: 1]
iex> reverse([42, "orange", ":atom"])
[":atom", "orange", 42]

"""

@spec reverse(list) :: list
def reverse(list) when is_list(list), do: reverse(list, [])
def reverse([head | tail], acc), do: reverse(tail, [head | acc])
def reverse([], acc), do: acc

@doc """
Places a new element at the end of an existing list

## Examples

iex> a = [1, 2, 3]
iex> b = ShittyLinqEx.append(a, 4)
[1, 2, 3, 4]
iex> c = ShittyLinqEx.append(b, 327)
[1, 2, 3, 4, 327]
"""

def append(list, new) do
list ++ [new]
end

@doc """
Returns the first element of a sequence.

## Parameters

- `list`: A sequence of values of which the first element should be returned.
- `predicate`: A function to check for each element
- `value`: A value which will be checked in the predicate function

## Returns

First value of the input sequence.

## Examples

iex> import ShittyLinqEx, only: [first: 1]
iex> first(["A", "B", "C"])
"A"

iex> import ShittyLinqEx, only: [first: 1]
iex> first([42, "orange", ":atom"])
42

iex> import ShittyLinqEx, only: [first: 3]
iex> first([4, 2, 3], &>/2, 1)
4

"""

def first(list) when is_list(list), do: List.first(list)
Expand Down Expand Up @@ -320,30 +295,22 @@ defmodule ShittyLinqEx do

@doc """
Filters a sequence of values based on a predicate.

## Parameters

- `source`: an enumerable to filter.
- `predicate`: a function to test each element for a condition.

## Returns

An enumerable that contains elements from the input sequence that satisfy the condition.

## Examples

iex> import ShittyLinqEx, only: [where: 2]
iex> where(
...> ["apple", "passionfruit", "banana", "mango", "orange", "blueberry", "grape", "strawberry"],
...> fn fruit -> String.length(fruit) < 6 end)
["apple", "mango", "grape"]

iex> import ShittyLinqEx, only: [where: 2]
iex> where(
...> [0, 30, 20, 15, 90, 85, 40, 75],
...> fn number, index -> number <= index * 10 end)
[0, 20, 15, 40]

"""
def where(source, predicate) when is_list(source) and is_function(predicate, 1) do
where_list(source, predicate)
Expand All @@ -369,6 +336,24 @@ defmodule ShittyLinqEx do
aggregate_range_dec(first - 1, last, func.(first, seed), func)
end

@doc """
Finds the sum of all values in a list with numeric elements.

## Examples

iex> list = [1, 2, 3]
iex> ShittyLinqEx.sum(list)
6
"""

def sum([]) do
0
end

def sum([h|t]) do
h + sum(t)
end

defp take_list([head | _], 1), do: [head]
defp take_list([head | tail], counter), do: [head | take_list(tail, counter - 1)]
defp take_list([], _counter), do: []
Expand Down