Flowdock
enum_for(*args) public

Returns Enumerator.new(self, method, *args).

e.g.:

str = "xyz"

enum = str.enum_for(:each_byte)
a = enum.map {|b| '%02x' % b } #=> ["78", "79", "7a"]

# protects an array from being modified
a = [1, 2, 3]
some_method(a.to_enum)
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August 23, 2008
3 thanks

Needs requiring 'enumerator' to work

This method needs that you

require 'enumerator'

for this method to be available.

May 27, 2009 - (>= v1_8_6_287)
2 thanks

map_with_index

If you want to access the element index when using map, you can do it with enum_for:

(1..6).enum_for(:each_with_index).map { |v, i| "index: #{i} value: #{v}" }
#=> ["index: 0 value: 1", "index: 1 value: 2", "index: 2 value: 3", "index: 3 value: 4", "index: 4 value: 5", "index: 5 value: 6"]