Revert "add back Hamming"

This reverts commit 6e1013d49c.

README.md

@@ -11,7 +11,6 @@ Distances are defined for `AbstractStrings`, and any iterator that define `lengt
 The available distances are:
 
 - Edit Distances
-	- [Hamming Distance](https://en.wikipedia.org/wiki/Hamming_distance) `Hamming()`
 	- [Jaro Distance](https://en.wikipedia.org/wiki/Jaro%E2%80%93Winkler_distance) `Jaro()`
 	- [Levenshtein Distance](https://en.wikipedia.org/wiki/Levenshtein_distance) `Levenshtein()`
 	- [Damerau-Levenshtein Distance](https://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance) `DamerauLevenshtein()`

src/StringDistances.jl

@@ -7,7 +7,7 @@ include("distances/edit.jl")
 include("distances/qgram.jl")
 include("normalize.jl")
 
-const StringDistance = Union{Hamming, Jaro, Levenshtein, DamerauLevenshtein, RatcliffObershelp, QGramDistance, Winkler, Partial, TokenSort, TokenSet, TokenMax, Normalize}
+const StringDistance = Union{Jaro, Levenshtein, DamerauLevenshtein, RatcliffObershelp, QGramDistance, Winkler, Partial, TokenSort, TokenSet, TokenMax, Normalize}
 # Distances API
 Distances.result_type(dist::StringDistance, s1, s2) = typeof(dist("", ""))
 include("find.jl")
@@ -21,7 +21,6 @@ include("find.jl")
 
 export
 StringDistance,
-Hamming,
 Levenshtein,
 DamerauLevenshtein,
 Jaro,

src/distances/edit.jl

@@ -1,16 +1,3 @@
-
-function (dist::Hamming)(s1::Union{AbstractString, Missing}, s2::Union{AbstractString, Missing}, max_dist::Union{Integer, Nothing} = nothing)
-    ((s1 === missing) | (s2 === missing)) && return missing
-    current = abs(length(s2) - length(s1))
-    max_dist !== nothing && current > max_dist && return max_dist + 1
-    for (ch1, ch2) in zip(s1, s2)
-        current += ch1 != ch2
-        max_dist !== nothing && current > max_dist && return max_dist + 1
-    end
-    return current
-end
-
-
 """
     Jaro()
 

src/normalize.jl

@@ -12,18 +12,8 @@ normalize(dist::SemiMetric) = Normalize(dist)
 normalize(dist::Normalize) = dist
 
 
-function (dist::Normalize{Hamming})(s1::AbstractString, s2::AbstractString; max_dist = 1.0)
-    s1, s2 = reorder(s1, s2)
-    len1, len2 = length(s1), length(s2)
-    len2 == 0 && return 1.0
-    out = evaluate(dist, s1, s2, max_dist * len2) / len2
-    out > max_dist ? 1.0 : out
-end
-
-
-
 # A normalized distance is between 0 and 1, and accept a third argument, max_dist.
-function (dist::Normalize{<: Union{Hamming, Levenshtein, DamerauLevenshtein}})(s1, s2, max_dist = 1.0)
+function (dist::Normalize{<: Union{Levenshtein, DamerauLevenshtein}})(s1, s2, max_dist = 1.0)
     ((s1 === missing) | (s2 === missing)) && return missing
     s1, s2 = reorder(s1, s2)
     len1, len2 = length(s1), length(s2)

test/distances.jl

@@ -3,14 +3,6 @@ using StringDistances, Unicode, Test
 
 @testset "Distances" begin
 
-	@testset "Hamming" begin
-		@test evaluate(Hamming(), "martha", "marhta") ≈  2
-		@test evaluate(Hamming(), "es an ", " vs an") ≈ 6
-		@test result_type(Hamming(), "hello", "world") == typeof(1)
-		@inferred evaluate(Hamming(), "", "")
-		@test ismissing(evaluate(Hamming(), "", missing))
-	end
-
 	@testset "Jaro" begin
 		@test evaluate(Jaro(), "martha", "marhta") ≈  0.05555555555555547
 		@test evaluate(Jaro(), "es an ", " vs an") ≈ 0.2777777777777777

test/modifiers.jl

@@ -16,10 +16,6 @@ using StringDistances, Unicode, Test
 	@test compare("martha", "martha", Overlap(2)) ≈ 1.0 atol = 1e-4
 	@test compare("martha", "martha", SorensenDice(2)) ≈ 1.0 atol = 1e-4
 
-	#Hamming
-	compare("aüa", "aua", Hamming()) ≈ 2/3 atol = 1e-4
-	compare("aaua", "aa", Partial(Hamming())) ≈ 1.0 atol = 1e-4
-
 	# Jaro
 	compare("aüa", "aua", Jaro())