Reference

Enumerable

Enumerable mixin methods shared across many collection types.

Enumerable#all?
Returns true if all elements in the collection satisfy the given condition. Returns true for empty collections.
Enumerable#any?
Returns true if any element satisfies the given condition. Checks truthiness when no block or argument is given.
Enumerable#chunk
Group consecutive elements by their block value with chunk in Ruby. Perfect for processing runs, states, or categorized data.
Enumerable#count
Counts elements in a collection that match a condition or returns the total number of elements.
Enumerable#cycle
Call the given block for each element n times or forever. Returns nil if the loop has finished without a break.
Enumerable#drop
Returns all elements after the first n elements. Use drop to skip calibration data, remove headers, or split collections into head and tail.
Enumerable#drop_while
Skips elements from the start of an enumerator while the condition is true, then returns the rest.
Enumerable#each_cons
Process consecutive elements in groups with each_cons. Perfect for sliding window algorithms, pairwise comparisons, and sequential analysis.
Enumerable#each_slice
Iterate over consecutive elements in fixed-size groups with each_slice. Useful for batch processing, pagination, and grouping data into chunks.
Enumerable#each_with_index
Iterates over each element while tracking its index position in the collection.

enum.each_with_index { |item, index| block } -> enum
Enumerable#each_with_object
Iterate over collection while building and returning an accumulator object with each_with_object in Ruby.
Enumerable#filter_map
Filter and transform elements in a single pass with filter_map in Ruby. Combines select and map for efficient processing.
Enumerable#find
Returns the first element that satisfies a given condition. Also available as detect, which is an alias.
Enumerable#first
Returns the first element or first n elements from a collection. Returns nil for empty collections when called without an argument.
Enumerable#flat_map
Transform and flatten collections in one pass with flat_map in Ruby. Combines map and flatten into an efficient operation.
Enumerable#group_by
Groups collection elements by a criteria and returns a hash with keys as group identifiers.
Enumerable#include?
Checks if any element equals the given object. Returns true or false.
Enumerable#inject
Reduces a collection to a single value by applying a binary operation repeatedly. Also known as reduce or fold in other languages.

enum.inject(initial) { |acc, elem| }
Enumerable#map
Returns a new array with the results of running block on every element. Also available as collect, which is an exact synonym.
Enumerable#max
Returns the largest element or n largest elements from an enumerable collection.
Enumerable#max_by
Find the maximum element in a collection based on the return value of a block with max_by in Ruby.
Enumerable#min
Returns the smallest element or n smallest elements from an enumerable collection.
Enumerable#min_by
Find the minimum element in a collection based on the return value of a block with min_by in Ruby.
Enumerable#none?
Returns true if no element satisfies the given condition. Checks for falsy values when no block or argument is given.
Enumerable#partition
Splits a collection into two arrays — elements for which the block returns true, and elements for which it returns false.
Enumerable#reduce
Reduces a collection to a single value by applying a binary operation repeatedly. Also known as inject or fold in other languages.

enum.reduce(initial) { |acc, elem| }
Enumerable#reject
Returns an array of all elements for which the block evaluates to false. The inverse of select — removes elements that match the condition.
Enumerable#select
Returns an array of all elements for which the block evaluates to true. Also available as find_all, which is an exact alias.
Enumerable#sort_by
Sort collection elements by criteria you define with sort_by in Ruby.
Enumerable#sum
Calculates the sum of elements in a collection. Adds all elements together with optional initial value and block transformation.
Enumerable#take
Returns the first n elements from a collection. Returns all elements if n exceeds the collection size — no error is raised.
Enumerable#take_while
Returns elements from the start of a collection while the condition is true. Stops as soon as the condition is false and discards the remaining elements.
Enumerable#tally
Counts occurrences of each element in a collection, returning a hash where keys are elements and values are their counts.
Enumerable#uniq
Returns a new array containing only the unique elements from a collection, preserving original order, with optional block for custom uniqueness logic.
Enumerable#zip
Merge multiple enumerables element-by-element with zip in Ruby. Creates arrays of corresponding elements, filling shorter ones with nil.