Is there a way to check if a NamedTuple has a field :a that is elided by the compiler? For example, let t=(a=1, b=2). Then the fact that t has fields :a,:b is known at compile time (because this info is in the type of t): julia> typeof(t) NamedTuple{(:a, :b),Tuple{Int64,Int64}} However both haskey…

[image] e3c6: This seems like a compiler bug? Should someone raise an issue? It is not a bug. But there is an issue open about it Constant propagation for tuple in operator only works for first element · Issue #28844 · JuliaLang/julia · GitHub . Also, the problem is not only with in but with p…

[image] e3c6: don’t seem to be elided by the compiler (I checked by looking at the @code_native of these calls). julia> t = (a = 3, b= 2) (a = 3, b = 2) julia> typeof(t) NamedTuple{(:a, :b),Tuple{Int64,Int64}} julia> f(t) = haskey(t, :a) f (generic function with 1 method) julia> @code_llvm…

Not really relevant here since: julia> b(t) = haskey(t, :b) b (generic function with 1 method) julia> @code_llvm b(t) ; @ REPL[42]:1 within `b' define i8 @julia_b_12946({ i64, i64 } addrspace(11)* nocapture nonnull readonly dereferenceable(16)) { top: ret i8 1 }

I thought it might still be relevant as the OP also mentions in instead of haskey. And there we have julia> @code_llvm :b in propertynames((a=2, b=3)) ; @ operators.jl:948 within `in' ; Function Attrs: uwtable define i8 @julia_in_10617(%jl_value_t addrspace(10)* nonnull, %jl_value_t addrspace(10)…

Okay. So for now I’ll use haskey instead of in. This seems like a compiler bug? Should someone raise an issue?

Zero-cost way to check if `NamedTuple` has a field?

General Usage

carstenbauer May 28, 2019, 10:23am 3

Topic		Replies	Views
`hasfield` and `getkey` in namedtuple General Usage question , syntax , base	5	193	September 25, 2025
Constant propagation with a namedtuple with one field General Usage	6	202	November 1, 2024
Is the first key of a NamedTuple special? General Usage	3	547	February 27, 2019
Slowness of fieldnames and propertynames Internals & Design	5	1147	March 10, 2021
Julia NaN check for NamedTuple General Usage nan , namedtuple	4	311	August 8, 2023

Zero-cost way to check if `NamedTuple` has a field?

Related topics