add delete for NamedTuple (#55270)

from #27725

Co-authored-by: Jeffrey Sarnoff <[email protected]>

Author: JeffBezanson

base/namedtuple.jl

@@ -424,6 +424,24 @@ function diff_fallback(a::NamedTuple, an::Tuple{Vararg{Symbol}}, bn::Tuple{Varar
     _new_NamedTuple(NamedTuple{names, types}, (A...,))
 end
 
+"""
+    delete(a::NamedTuple, field::Symbol)
+
+Construct a new named tuple from `a` by removing the named field.
+
+```jldoctest
+julia> Base.delete((a=1, b=2, c=3), :a)
+(b = 2, c = 3)
+
+julia> Base.delete((a=1, b=2, c=3), :b)
+(a = 1, c = 3)
+```
+"""
+@constprop :aggressive function delete(a::NamedTuple{an}, field::Symbol) where {an}
+    names = diff_names(an, (field,))
+    NamedTuple{names}(a)
+end
+
 """
     structdiff(a::NamedTuple, b::Union{NamedTuple,Type{NamedTuple}})
 

test/namedtuple.jl

@@ -1,5 +1,7 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
+using Base: delete
+
 @test_throws TypeError NamedTuple{1,Tuple{}}
 @test_throws TypeError NamedTuple{(),1}
 @test_throws TypeError NamedTuple{(:a,1),Tuple{Int}}
@@ -282,6 +284,11 @@ end
 abstr_nt_22194_3()
 @test Base.return_types(abstr_nt_22194_3, ()) == Any[Any]
 
+@test delete((a=1,), :a) == NamedTuple()
+@test delete((a=1, b=2), :a) == (b=2,)
+@test delete((a=1, b=2, c=3), :b) == (a=1, c=3)
+@test delete((a=1, b=2, c=3), :z) == (a=1, b=2, c=3)
+
 @test Base.structdiff((a=1, b=2), (b=3,)) == (a=1,)
 @test Base.structdiff((a=1, b=2, z=20), (b=3,)) == (a=1, z=20)
 @test Base.structdiff((a=1, b=2, z=20), (b=3, q=20, z=1)) == (a=1,)