rewrite indexin function according to @timholy and using comprehe…

…nsion rename to indexin rename to indexin
JuliaLang · Jul 25, 2013 · 88b0c57 · 88b0c57
1 parent a631ca0
commit 88b0c57
Show file tree

Hide file tree

Showing 3 changed files with 14 additions and 0 deletions.
diff --git a/base/array.jl b/base/array.jl
@@ -1371,6 +1371,13 @@ end
 indmax(a) = findmax(a)[2]
 indmin(a) = findmin(a)[2]
 
+# similar to Matlab's ismember
+# returns a vector containing the highest index in b for each value in a that is a member of b
+function indexin{T}(a::AbstractArray{T}, b::AbstractArray{T})
+    bdict = Dict(b, 1:length(b))
+    [get(bdict, i, 0) for i in a]
+end
+
 # findin (the index of intersection)
 function findin(a, b::Range1)
     ind = Array(Int, 0)

diff --git a/base/exports.jl b/base/exports.jl
@@ -491,6 +491,7 @@ export
     hcat,
     hvcat,
     ind2sub,
+    indexin,
     indmax,
     indmin,
     invperm,

diff --git a/doc/stdlib/base.rst b/doc/stdlib/base.rst
@@ -304,6 +304,12 @@ Iterable Collections
 .. function:: contains(itr, x) -> Bool
 
    Determine whether a collection contains the given value, ``x``.
+
+.. function:: indexin(a, b)
+
+   Returns a vector containing the highest index in ``b``
+   for each value in ``a`` that is a member of ``b`` .
+   The output vector contains 0 wherever ``a`` is not a member of ``b``.
 
 .. function:: findin(a, b)