Sha256: 4b7f799da94d3aef50e98201d3ccdb380dc2f52771606da8125758202209f64c
Contents?: true
Size: 1.73 KB
Versions: 10
Compression:
Stored size: 1.73 KB
Contents
# TITLE:
#
# Hash Traversal Extensions
#
# SUMMARY:
#
# Traversal extensions for Hash class.
#
# CREDITS:
#
# - Thomas Sawyer
#
class Hash
# Returns a new hash created by traversing the hash and its subhashes,
# executing the given block on the key and value. The block should
# return a 2-element array of the form +[key, value]+.
#
# h = { "A"=>"A", "B"=>"B" }
# g = h.traverse { |k,v| [k.downcase, v] }
# g #=> { "a"=>"A", "b"=>"B" }
#
#--
# TODO Testing value to see if it is a Hash also catches subclasses of Hash.
# This is probably not the right thing to do and should catch Hashes only (?)
#++
def traverse(&b)
inject({}) do |h,(k,v)|
v = ( Hash === v ? v.traverse(&b) : v )
nk, nv = b[k,v]
h[nk] = nv #( Hash === v ? v.traverse(base,&b) : nv )
h
end
end
# In place version of traverse, which traverses the hash and its
# subhashes, executing the given block on the key and value.
#
# h = { "A"=>"A", "B"=>"B" }
# h.traverse! { |k,v| [k.downcase, v] }
# h #=> { "a"=>"A", "b"=>"B" }
#
def traverse!(&b)
self.replace( self.traverse(&b) )
end
end
# _____ _
# |_ _|__ ___| |_
# | |/ _ \/ __| __|
# | | __/\__ \ |_
# |_|\___||___/\__|
#
=begin test
require 'test/unit'
class TestHashTraverse < Test::Unit::TestCase
def test_traverse
h = { "A" => "x", "B" => "y" }
h2 = h.traverse { |k,v| [k.downcase, v.upcase] }
e = { "a" => "X", "b" => "Y" }
assert_not_equal( h, h2 )
assert_equal( e, h2 )
end
def test_traverse!
h = { "A" => "x", "B" => "y" }
h.traverse! { |k,v| [k.downcase, v.upcase] }
e = { "a" => "X", "b" => "Y" }
assert_equal( e, h )
end
end
=end
Version data entries
10 entries across 10 versions & 1 rubygems