From 51be6ac1dbf47e2cb601f657c5b3b59b66caa7cb Mon Sep 17 00:00:00 2001
From: Jeff Bezanson <jeff.bezanson@gmail.com>
Date: Fri, 21 Jul 2017 16:46:43 -0400
Subject: [PATCH] use `pairs` in `findmin` and `findmax`, supporting all
 indexable collections

---
 base/array.jl    | 24 ++++++++++++------------
 test/arrayops.jl |  5 +++++
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/base/array.jl b/base/array.jl
index bd5cda891903a..1e2d0469c3858 100644
--- a/base/array.jl
+++ b/base/array.jl
@@ -1717,12 +1717,12 @@ function findmax(a)
     if isempty(a)
         throw(ArgumentError("collection must be non-empty"))
     end
-    s = start(a)
-    mi = i = 1
-    m, s = next(a, s)
-    while !done(a, s)
-        ai, s = next(a, s)
-        i += 1
+    p = pairs(a)
+    s = start(p)
+    (mi, m), s = next(p, s)
+    i = mi
+    while !done(p, s)
+        (i, ai), s = next(p, s)
         if ai > m || m!=m
             m = ai
             mi = i
@@ -1756,12 +1756,12 @@ function findmin(a)
     if isempty(a)
         throw(ArgumentError("collection must be non-empty"))
     end
-    s = start(a)
-    mi = i = 1
-    m, s = next(a, s)
-    while !done(a, s)
-        ai, s = next(a, s)
-        i += 1
+    p = pairs(a)
+    s = start(p)
+    (mi, m), s = next(p, s)
+    i = mi
+    while !done(p, s)
+        (i, ai), s = next(p, s)
         if ai < m || m!=m
             m = ai
             mi = i
diff --git a/test/arrayops.jl b/test/arrayops.jl
index 66715a1bd3308..9518e63974d47 100644
--- a/test/arrayops.jl
+++ b/test/arrayops.jl
@@ -1796,6 +1796,11 @@ s, si = findmax(S)
 @test a == b == s
 @test ai == bi == si
 
+for X in (A, B, S)
+    @test findmin(X) == findmin(Dict(pairs(X)))
+    @test findmax(X) == findmax(Dict(pairs(X)))
+end
+
 fill!(B, 2)
 @test all(x->x==2, B)