Lua LINQ Library Documentation

A functional approach to working with collections in Lua, inspired by .NET LINQ.

Enumerator

Enumerator provides a chainable API for collection operations. Each method returns a new Enumerator instance.

Creation Methods

EnumeratorCreate(iterator, transformer)

• Creates a new Enumerator instance
• Parameters:
  • iterator: Function that iterates over collection
  • transformer: Optional function that transforms the input collection
• Returns: New Enumerator instance

Transformation Methods

:Select(selector)

• Projects each element into a new form
• Parameters:
  • selector: Function (value, key) -> result or string/number key
• Returns: New Enumerator with transformed elements

:Where(condition)

• Filters elements based on a predicate
• Parameters:
  • condition: Function (value, key) -> boolean
• Returns: New Enumerator with filtered elements

:Distinct()

• Returns distinct elements from the sequence
• Returns: New Enumerator with duplicate elements removed

:GroupBy(selector)

• Groups elements by key selector
• Parameters:
  • selector: Function (value, key) -> groupKey
• Returns: New Enumerator with grouped elements

:OrderBy(selector, comparer?)

• Sorts elements in sequence by key selector
• Parameters:
  • selector: Function (value) -> key
  • comparer: Optional function (left, right) -> boolean
• Returns: New Enumerator with sorted elements

:OrderByDescending(selector, comparer?)

• Sorts elements in sequence by key selector
• Parameters:
  • selector: Function (value) -> key
  • comparer: Optional function (left, right) -> boolean
• Returns: New Enumerator with sorted elements in descending order

:Reverse()

• Reverses the sequence
• Returns: New Enumerator with reversed elements

:AsSet()

• Converts sequence to set (table with true values)
• Returns: New Enumerator representing set

Terminal Operations

:Execute(callback)

• Executes callback for each element
• Parameters:
  • callback: Function (value, key)
• Returns: Function that performs the execution

:ToArray()

• Converts sequence to array
• Returns: Function that produces array

:ToTable(selector)

• Converts sequence to table
• Parameters:
  • selector: Optional function (key, value) -> newKey, newValue
• Returns: Function that produces table

:Min(comparer)

• Finds minimum element
• Parameters:
  • comparer: Optional function (left, right) -> boolean
• Returns: Function that returns minimum value

:Max(comparer)

• Finds maximum element
• Parameters:
  • comparer: Optional function (left, right) -> boolean
• Returns: Function that returns maximum value

:Average()

• Calculates average of numeric sequence
• Returns: Function that returns average value

:Sum()

• Calculates sum of numeric sequence
• Returns: Function that returns sum

:Count(condition)

• Counts elements matching condition
• Parameters:
  • condition: Optional function (value, key) -> boolean
• Returns: Function that returns count

Enumerable

Enumerable provides similar functionality but modifies the existing instance instead of creating new ones.

Creation Methods

EnumerableCreate(t, iterator, transformer)

• Creates new Enumerable instance
• Parameters:
  • t: Source table
  • iterator: Optional iterator function
  • transformer: Optional transformer function
• Returns: New Enumerable instance

Transformation Methods

Same method names and parameters as Enumerator, but modifies current instance:

• :Select(selector)
• :Where(condition)
• :Distinct()
• :GroupBy(selector)
• :Sort(comparer)
• :Reverse()
• :AsSet()

Additional Methods

:Clone()

• Creates copy of current Enumerable
• Returns: New Enumerable instance

:Cache()

• Creates new Enumerable with cached results
• Returns: New Enumerable with materialized results

Terminal Operations

Same method names and parameters as Enumerator, but returns results directly instead of functions:

• :Execute(callback)
• :ToArray()
• :ToTable(selector)
• :Min(comparer)
• :Max(comparer)
• :Average()
• :Sum()
• :Count(condition)

Usage Example

-- Using Enumerator
local enumerator = EnumeratorCreate(_ipairs)
    :Where(function(v) return v > 5 end)
    :Select(function(v) return v * 2 end)
    :ToArray()

local t = enumerator({1,2,3,4,5,6,7,8,9,10})

-- Using Enumerable
local result = EnumerableCreate({1,2,3,4,5,6,7,8,9,10})
    :Where(function(v) return v > 5 end)
    :Select(function(v) return v * 2 end)
    :ToArray()

Enumerator

Method	Description
:__call(t)	Returns iterator and transformed table for iteration within for loop
:Where(condition)	Filters elements based on a predicate
:Select(selector)	Projects each element into a new form
:Keys()	Returns keys of the table
:Distinct()	Returns distinct elements from the sequence keeping original order
:Foreach(func)	Executes a function for each element
:Reverse()	Reverses the sequence
:GroupBy(selector)	Groups elements by key selector
:OrderBy(selector, comparer?)	Sorts elements in sequence
:OrderByDescending(selector, comparer?)	Sorts elements in sequence in descending order
:SelectMany(selector?)	Projects each element of a sequence and flattens the resulting sequences into one sequence
:Execute(func)	Executes a function for each element
:Min(comparer?)	Finds minimum element
:Max(comparer?)	Finds maximum element
:Any(condition?)	Checks if any element matches condition
:All(condition?)	Checks if all elements match condition
:First(condition?)	Returns first element that matches condition
:Last(condition?)	Returns last element that matches condition
:Aggregate(func, initial)	Applies a function to each element and accumulates the result
:Average()	Calculates average of numeric sequence
:Count(condition?)	Counts elements matching condition
:Sum()	Calculates sum of numeric sequence
:Contains(value)	Checks if sequence contains a specific value
:ToFunction()	Returns function that returns iterator and transformed table for iteration within for loop
:ToIterator()	Returns iterator with scoped table for iteration within for loop
:ToArray()	Converts sequence to array
:ToSet()	Returns set of elements
:ToTable(selector?)	Converts sequence to table with optional key-value selector

Enumerable

Method	Description
:__call()	Returns iterator and transformed table for iteration within for loop
:Clone()	Creates copy of current Enumerable
:Where(condition)	Filters elements based on a predicate
:Select(selector)	Projects each element into a new form
:Keys()	Returns keys of the table
:Distinct()	Returns distinct elements from the sequence keeping original order
:Select(selector)	Projects each element into a new form
:Keys()	Returns keys of the table
:Distinct()	Returns distinct elements from the sequence keeping original order
:Foreach(func)	Executes a function for each element
:Reverse()	Reverses the sequence
:GroupBy(selector)	Groups elements by key selector
:OrderBy(selector, comparer?)	Sorts elements in sequence
:OrderByDescending(selector, comparer?)	Sorts elements in sequence in descending order
:SelectMany(selector?)	Projects each element of a sequence and flattens the resulting sequences into one sequence
:Execute(func)	Executes a function for each element
:Cache()	Creates new Enumerable with cached table after transformation
:First(condition?)	Returns first element that matches condition
:Last(condition?)	Returns last element that matches condition
:Average()	Calculates average of numeric sequence
:Count(condition?)	Counts elements matching condition
:Aggregate(func, initial)	Applies a function to each element and accumulates the result
:Sum()	Calculates sum of numeric sequence
:Contains(value)	Checks if sequence contains a specific value
:Min(comparer?)	Finds minimum element
:Max(comparer?)	Finds maximum element
:All(condition?)	Checks if all elements match condition
:Any(condition?)	Checks if any element matches condition
:ToArray()	Converts sequence to array
:ToSet()	Returns set of elements
:ToTable(selector?)	Converts sequence to table with optional key-value selector