Add isfound

base/operators.jl

@@ -874,4 +874,20 @@ julia> map(splat(+), zip(1:3,4:6))
  9
 ```
 """
-splat(f) = args->f(args...)
+splat(f) = args->f(args...)
+
+"""
+    isfound(needle, haystack)
+
+Determine whether `needle` is found within the collection `haystack`.
+
+# Examples
+```jldoctest
+julia> isfound("wor", "Hello, world!")
+true
+
+julia> isfound(r"\d\+", "No numbers here")
+false
+```
+"""
+isfound(needle, haystack) = findfirst(needle, haystack) !== nothing

base/regex.jl

@@ -220,6 +220,8 @@ findnext(r::Regex, s::AbstractString, idx::Integer) = throw(ArgumentError(
 ))
 findfirst(r::Regex, s::AbstractString) = findnext(r,s,firstindex(s))
 
+isfound(r::Regex, s::AbstractString) = contains(s, r)
+
 struct SubstitutionString{T<:AbstractString} <: AbstractString
     string::T
 end

doc/src/base/arrays.md

@@ -129,6 +129,7 @@ Base.findnext(::Any, ::Integer)
 Base.findnext(::Function, ::Any, ::Integer)
 Base.findprev(::Any, ::Integer)
 Base.findprev(::Function, ::Any, ::Integer)
+Base.isfound
 Base.permutedims
 Base.permutedims!
 Base.PermutedDimsArray

test/arrayops.jl

@@ -476,6 +476,13 @@ end
     @test findprev(iseven, A, CartesianIndex(2, 1)) === nothing
 end
 
+@testset "isfound" begin
+    @test isfound(isodd, [1, 2, 3])
+    @test isfound(equalto(0x01), [0x00, 0x01, 0x02])
+    @test !isfound(x->x > 4, [1, 2, 3])
+    @test !isfound(isnan, [0.0, 4.5, 2.2])
+end
+
 @testset "findmin findmax argmin argmax" begin
     @test argmax([10,12,9,11]) == 2
     @test argmin([10,12,9,11]) == 3

test/regex.jl

@@ -49,3 +49,6 @@ end
 
 # Proper unicode handling
 @test  match(r"∀∀", "∀x∀∀∀").match == "∀∀"
+
+@test isfound(r"\d\+", "abc123")
+@test !isfound(r"[^_]", "___")

test/strings/search.jl

@@ -327,4 +327,9 @@ end
 
 @test @inferred findall(equalto('a'), "éa") == [3]
 @test @inferred findall(equalto('€'), "€€") == [1, 4]
-@test @inferred isempty(findall(equalto('é'), ""))
+@test @inferred isempty(findall(equalto('é'), ""))
+
+@test isfound(equalto('x'), "xylophone")
+@test isfound("hi", "hi, mom")
+@test !isfound("elephant", "zoo")
+@test !isfound(equalto('3'), "124")