adding tests to unzip

base/iterators.jl

@@ -240,6 +240,28 @@ end
 iteratorsize{I1,I2}(::Type{Zip{I1,I2}}) = zip_iteratorsize(iteratorsize(I1),iteratorsize(I2))
 iteratoreltype{I1,I2}(::Type{Zip{I1,I2}}) = and_iteratoreltype(iteratoreltype(I1),iteratoreltype(I2))
 
+# unzip
+```jldoctest
+
+For iterable objects of the same length, returns iterable sets, where the ith set contains
+the ith component of each input iterable object. 
+
+julia>  z = [[1,"a",:meow], [2,"b",:woof], [3,"c",:doh!]]
+3-element Array{Array{Any,1},1}:
+Any[1, "a", :meow]
+Any[2, "b", :woof]
+Any[3, "c", :doh!]                                                                                         
+
+julia> unzip(z)
+Array{Int64,1}:[1,2,3]
+Array{String,1}["a","b","c"]
+Array{Symbol,1}[:meow,:woof,:doh!]
+```
+function unzip(z)
+    [z[j][i] for i=1:length(z), j=length(z)]
+end
+
+
 # filter
 
 struct Filter{F,I}

test/iterators.jl

@@ -22,6 +22,22 @@ let z = zip(1:2, 3:4, 5:6)
     @test eltype(z) == Tuple{Int,Int,Int}
 end
 
+# unzip
+let z = zip(1:2)
+    @test unzip(z) == [1:2]
+    @test eltype(unzip(z)) == UnitRange{Int64}
+end
+
+let z = zip(1:2, 3:4)
+    @test collect(unzip(z)) == [(1,2), (3,4)]
+    @test eltype(unzip(z)) == UnitRange{Int64}
+end
+
+let z = zip(1:2, 3:4, 5:6)
+    @test collect(unzip(z)) == [(1,2), (3,4), (5,6)]
+    @test eltype(unzip(z)) == UnitRange{Int64}
+end
+
 @test eltype(Iterators.filter(isodd, 1:5)) == Int
 
 # typed `collect`