add searchsorted_interval (#109)

* add searchsorted_interval Co-authored-by: hyrodium <[email protected]> * bump version Co-authored-by: hyrodium <[email protected]>
JuliaMath · May 31, 2022 · b3f0d6e · b3f0d6e · hyrodium · May 31, 2022
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Showing 4 changed files with 57 additions and 2 deletions.
diff --git a/Project.toml b/Project.toml
@@ -1,6 +1,6 @@
 name = "IntervalSets"
 uuid = "8197267c-284f-5f27-9208-e0e47529a953"
-version = "0.7.0"
+version = "0.7.1"
 
 [deps]
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"

diff --git a/src/IntervalSets.jl b/src/IntervalSets.jl
@@ -14,7 +14,8 @@ export AbstractInterval, Interval, OpenInterval, ClosedInterval,
             ⊇, .., ±, ordered, width, leftendpoint, rightendpoint, endpoints,
             isopenset, isclosedset, isleftclosed, isrightclosed,
             isleftopen, isrightopen, closedendpoints,
-            infimum, supremum
+            infimum, supremum,
+            searchsorted_interval
 
 """
 A subtype of `Domain{T}` represents a subset of type `T`, that provides `in`.

diff --git a/src/findall.jl b/src/findall.jl
@@ -83,3 +83,28 @@ function Base._findin(a::Union{AbstractArray, Tuple}, b::Interval)
     end
     ind
 end
+
+"""
+    searchsorted_interval(a, i::Interval)
+
+Return the range of indices of `a` which is inside of the interval `i` (using binary search), assuming that
+`a` is already sorted. Return an empty range located at the insertion point if a does not contain values in `i`.
+
+# Examples
+```jldoctest
+julia> searchsorted_interval([1,2,3,5], 2..4)
+2:3
+
+julia> searchsorted_interval([1,2,3,5], 4..1)
+4:3
+
+julia> searchsorted_interval(Float64[], 1..3)
+1:0
+```
+"""
+function searchsorted_interval end
+
+searchsorted_interval(X, i::Interval{:closed, :closed}) = searchsortedfirst(X, leftendpoint(i))     :searchsortedlast(X, rightendpoint(i))
+searchsorted_interval(X, i::Interval{:closed,   :open}) = searchsortedfirst(X, leftendpoint(i))     :(searchsortedfirst(X, rightendpoint(i)) - 1)
+searchsorted_interval(X, i::Interval{  :open, :closed}) = (searchsortedlast(X, leftendpoint(i)) + 1):searchsortedlast(X, rightendpoint(i))
+searchsorted_interval(X, i::Interval{  :open,   :open}) = (searchsortedlast(X, leftendpoint(i)) + 1):(searchsortedfirst(X, rightendpoint(i)) - 1)
diff --git a/test/findall.jl b/test/findall.jl
@@ -149,4 +149,33 @@ end
             assert_in_interval(reverse(x), interval)
         end
     end
+
+    @testset "searchsorted" begin
+        x = [-10, 0, 1, 1 + eps(), 1.2, 1.5, 1.9, 2 - eps(), 2]
+        @test searchsorted_interval(x, -Inf..Inf) == 1:9
+        i = Interval{:closed, :closed}(1, 2)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 3:9
+        i = Interval{:open  , :closed}(1, 2)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 4:9
+        i = Interval{:closed, :open  }(1, 2)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 3:8
+        i = Interval{:open  , :open  }(1, 2)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 4:8
+        i = Interval{:closed, :closed}(1, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 3:3
+        i = Interval{:open  , :closed}(1, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 3:2
+        i = Interval{:closed, :open  }(1, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 3:2
+        i = Interval{:open  , :open  }(1, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 3:2
+        i = Interval{:closed, :closed}(2, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 9:8
+        i = Interval{:open  , :closed}(2, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 9:8
+        i = Interval{:closed, :open  }(2, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 9:8
+        i = Interval{:open  , :open  }(2, 1)
+        @test searchsorted_interval(x, i) == findall(in(i),x) == 9:8
+    end
 end