[RFC] support multiple s=>r Pairs in strings replace method

base/strings/util.jl

@@ -526,6 +526,57 @@ replace(s::AbstractString, pat_f::Pair; count=typemax(Int)) =
 
 # TODO: allow transform as the first argument to replace?
 
+@inline rangify(c::T) where T<:AbstractRange = c
+@inline rangify(c::T) where T<:Integer = c:c
+@inline rangify(c::Nothing) = c
+
+function multi_replace(str::String,count::Integer,subs::NTuple{N,Pair}) where N
+    sh=floor(Int,1.2sizeof(str))
+    @inbounds(count > 0 && for si in 1:N
+        s,r = subs[si]
+        R=rangify(findfirst(s,str))
+        isnothing(R) && continue
+        buf = IOBuffer(sizehint = sh)
+        i,j = first(R),last(R)
+        H,n = multi_replace(str[begin:(i - 1)], count, subs[(si + 1):end])
+        count -= n
+        totrepl = n
+        print(buf,H)
+        if count > 0
+            print(buf,replace(str[R],s=>r))
+            count -= 1
+            totrepl += 1
+        else
+            print(buf,str[R])
+        end
+        T,n=multi_replace(str[(j + 1):end], count, subs)
+        totrepl += n
+        print(buf,T)
+        return String(take!(buf)), totrepl
+    end)
+    str, 0
+end
+
+function replace(str::String, subs::Pair...; count::Integer=typemax(Int))
+    multi_replace(str, count, subs)[1]
+end
+
+const _ReplaceCharToTS=Pair{Char,B} where {B<:Union{AbstractChar,AbstractString,Number}}
+function replace(str::String,mapping::_ReplaceCharToTS...;count::Integer = typemax(Int))
+    d=Dict(mapping...)
+    sizestr = sizeof(str)
+    buf = IOBuffer(sizehint=sizestr+sizestr>>1)
+    for c in str
+        if count > 0 && haskey(d,c)
+            count -= 1
+            print(buf,@inbounds d[c])
+        else
+            print(buf, c)
+        end
+    end
+    String(take!(buf))
+end
+
 # hex <-> bytes conversion
 
 """

test/strings/util.jl

@@ -297,6 +297,16 @@ end
     @test replace("a", in("a") => typeof) == "Char"
     @test replace("a", ['a'] => typeof) == "Char"
 
+    # PR 35414
+    @test replace("foobarbaz","oo"=>"zz","ar"=>"zz","z"=>"m") == "fzzbzzbam"
+    substmp=["z"=>"m","oo"=>"zz","ar"=>"zz"]
+    for perm in [[1,2,3],[2,1,3],[3,2,1],[2,3,1],[1,3,2],[3,1,2]]
+        @test replace("foobarbaz",substmp[perm]...) == "fzzbzzbam"
+        @test replace("foobarbaz",substmp[perm]...,count=2) == "fzzbzzbaz"
+        @test replace("foobarbaz",substmp[perm]...,count=1) == "fzzbarbaz"
+    end
+    @test replace("foobarbaz","z"=>"m",r"a.*a"=>uppercase) == "foobARBAm"
+    @test replace("foobarbaz",'o'=>'z','a'=>'q','z'=>'m') == "fzzbqrbqm"
 end
 
 @testset "chomp/chop" begin