each, map, select - ruby

enumerators.rb

# each
h = [10, 20, 30]
hh = h.each {|e| e*2 } # does not create new object
# print h
# print h.object_id == hh.object_id # true

# map
x = [1, 2, 3]
z = x.map { |e| e*2 } # does create new object - non-destructive manner
# print x
# print x.object_id == z.object_id # false
# print z

foo = x.map! { |e| e*2 } # does not create new object - destructive manner
# print foo.object_id == x.object_id # true

# select
bar = [12, 15, 29, 19]
baz = bar.select {|e| e > 18 }
print bar #[12, 15, 29, 19]
print baz #[29, 19]
print bar.object_id == baz.object_id # false

# collect
# same as map