Allow dropdims with reduction to take mutliple args and kwargs

NEWS.md

@@ -26,14 +26,12 @@ New library functions
 * The `tempname` function now takes a `cleanup::Bool` keyword argument defaulting to `true`, which causes the process to try to ensure that any file or directory at the path returned by `tempname` is deleted upon process exit ([#33090]).
 * The `readdir` function now takes a `join::Bool` keyword argument defaulting to `false`, which when set causes `readdir` to join its directory argument with each listed name ([#33113]).
 
-
 Standard library changes
 ------------------------
 
 * The methods of `mktemp` and `mktempdir` which take a function body to pass temporary paths to no longer throw errors if the path is already deleted when the function body returns ([#33091]).
 
-* A new `squeeze(f, A, dims)` method computes the reduction `f` over the region in
-`A` described by `dims` and then drops those dimensions from the result ([#23500]).
+* A new `dropdims(f, args...; dims, kwargs...)` method computes the reduction `f` over the region described by `dims` and then drops those dimensions from the result ([#23500]).
 
 #### Libdl
 

base/abstractarraymath.jl

@@ -88,11 +88,31 @@ end
 _dropdims(A::AbstractArray, dim::Integer) = _dropdims(A, (Int(dim),))
 
 """
-    squeeze(f, A, dims)
+    dropdims(f, args...; dims, kwargs...)
 
-Compute reduction `f` over dimensions `dims` in array `A` and drop those dimensions from the result.
+Compute reduction `f` over dimensions `dims` and drop those dimensions from the result.
+
+# Examples
+```jldoctest
+julia> a = [3.0  2.0  6.0  8.0
+            6.0  1.0  4.0  2.0
+            3.0  0.0  7.0  6.0];
+
+julia> dropdims(sum, a, dims=1)
+4-element Array{Float64,1}:
+ 12.0
+  3.0
+ 17.0
+ 16.0
+
+julia> dropdims(sum, abs2, a, dims=2)
+3-element Array{Float64,1}:
+ 113.0
+  57.0
+  94.0
+```
 """
-squeeze(f, A::AbstractArray, dims::Union{Dims, Integer}) = squeeze(f(A, dims), dims)
+dropdims(f, args...; dims, kwargs...) = _dropdims(f(args...; kwargs..., dims=dims), dims)
 
 ## Unary operators ##
 

test/arrayops.jl

@@ -303,16 +303,36 @@ end
     @test_throws ArgumentError dropdims(a, dims=4)
     @test_throws ArgumentError dropdims(a, dims=6)
 
-    @test @inferred(squeeze(sum, a, 1)) == @inferred(squeeze(sum, a, (1,))) == reshape(sum(a, 1), (1, 8, 8, 1))
-    @test @inferred(squeeze(sum, a, 3)) == @inferred(squeeze(sum, a, (3,))) == reshape(sum(a, 3), (1, 1, 8, 1))
-    @test @inferred(squeeze(sum, a, 4)) == @inferred(squeeze(sum, a, (4,))) == reshape(sum(a, 4), (1, 1, 8, 1))
-    @test @inferred(squeeze(sum, a, (1, 5))) == squeeze(sum, a, (5, 1)) == reshape(sum(a, (5, 1)), (1, 8, 8))
-    @test @inferred(squeeze(sum, a, (1, 2, 5))) == squeeze(sum, a, (5, 2, 1)) == reshape(sum(a, (5, 2, 1)), (8, 8))
-    @test_throws ArgumentError squeeze(sum, a, 0)
-    @test_throws ArgumentError squeeze(sum, a, (1, 1))
-    @test_throws ArgumentError squeeze(sum, a, (1, 2, 1))
-    @test_throws ArgumentError squeeze(sum, a, (1, 1, 2))
-    @test_throws ArgumentError squeeze(sum, a, 6)
+    # dropdims with reductions. issue #16606
+    @test (@inferred(dropdims(sum, a, dims=1)) ==
+           @inferred(dropdims(sum, a, dims=(1,))) ==
+           reshape(sum(a, dims=1), (1, 8, 8, 1)))
+    @test (@inferred(dropdims(sum, a, dims=3)) ==
+           @inferred(dropdims(sum, a, dims=(3,))) ==
+           reshape(sum(a, dims=3), (1, 1, 8, 1)))
+    @test (@inferred(dropdims(sum, a, dims=4)) ==
+           @inferred(dropdims(sum, a, dims=(4,))) ==
+           reshape(sum(a, dims=4), (1, 1, 8, 1)))
+    @test (@inferred(dropdims(sum, a, dims=(1, 5))) ==
+           dropdims(sum, a, dims=(5, 1)) ==
+           reshape(sum(a, dims=(5, 1)), (1, 8, 8)))
+    @test (@inferred(dropdims(sum, a, dims=(1, 2, 5))) ==
+           dropdims(sum, a, dims=(5, 2, 1)) ==
+           reshape(sum(a, dims=(5, 2, 1)), (8, 8)))
+    @test (@inferred(dropdims(sum, abs2, a, dims=1)) ==
+           @inferred(dropdims(sum, abs2, a, dims=(1,))) ==
+           reshape(sum(abs2, a, dims=1), (1, 8, 8, 1)))
+    _sumplus(x; dims, plus) = sum(x; dims=dims) .+ plus  # reduction with keywords
+    @test (@inferred(dropdims(_sumplus, a, dims=4, plus=1)) ==
+           @inferred(dropdims(_sumplus, a, dims=(4,), plus=1)) ==
+           reshape(sum(a, dims=4) .+ 1, (1, 1, 8, 1)))
+    @test_throws UndefKeywordError dropdims(sum, a)
+    @test_throws UndefKeywordError dropdims(sum, a, 1)
+    @test_throws ArgumentError dropdims(sum, a, dims=0)
+    @test_throws ArgumentError dropdims(sum, a, dims=(1, 1))
+    @test_throws ArgumentError dropdims(sum, a, dims=(1, 2, 1))
+    @test_throws ArgumentError dropdims(sum, a, dims=(1, 1, 2))
+    @test_throws ArgumentError dropdims(sum, a, dims=6)
 
     sz = (5,8,7)
     A = reshape(1:prod(sz),sz...)