Ruby | Enumerable group_by() function

The group_by() of enumerable is an inbuilt method in Ruby returns an hash where the groups are collectively kept as the result of the block after grouping them. In case no block is given, then an enumerator is returned.

Syntax: enu.group_by { |obj| block }

Parameters: The function takes an optional block according to which grouping is done.

Return Value: It returns a hash.

Example #1:

# Ruby program for group_by method in Enumerable

# Initialize
enu = (1..10)

# Prints
enu.group_by { |obj| obj % 4 == 1 }

Output:

{true=>[1, 5, 9], false=>[2, 3, 4, 6, 7, 8, 10]}

Example #2:

# Ruby program for group_by method in Enumerable

# Initialize
enu = [2, 8, 9, 10, 23]

# Prints
enu.group_by { |obj| obj % 6 }

Output:

{2=>[2, 8], 3=>[9], 4=>[10], 5=>[23]}