Apply suggestion to return Float64 for scalars; update docstring and tests accordingly

Author: GianmarcoCuppari

src/symmetric.jl

@@ -1003,21 +1003,26 @@ end
 
 """
     hermitianpart(A::AbstractMatrix, uplo::Symbol=:U) -> Hermitian
-    hermitianpart(x::Number) -> Real
+    hermitianpart(x::Number) -> Number
 
 Return the Hermitian part of the square matrix `A`, defined as `(A + A') / 2`, as a
 [`Hermitian`](@ref) matrix. For real matrices `A`, this is also known as the symmetric part
 of `A`; it is also sometimes called the "operator real part". The optional argument `uplo` controls the corresponding argument of the
 [`Hermitian`](@ref) view. For real matrices, the latter is equivalent to a
 [`Symmetric`](@ref) view.
 
+For scalar inputs `x`, the function returns the real part of `x`. Standard integer scalars
+are promoted to `Float64` to align with the behavior of 1×1 Hermitian matrices, while other numeric types
+(`Float32`, `BigInt`, `Rational`, `BigFloat`) are preserved.
+
 See also [`hermitianpart!`](@ref) for the corresponding in-place operation.
 
 !!! compat "Julia 1.10"
     This function requires Julia 1.10 or later.
 """
+
 hermitianpart(A::AbstractMatrix, uplo::Symbol=:U) = Hermitian(_hermitianpart(A), uplo)
-hermitianpart(x::Number) = real(x)
+hermitianpart(x::Number) = float(real(x))
 
 """
     hermitianpart!(A::AbstractMatrix, uplo::Symbol=:U) -> Hermitian
@@ -1054,4 +1059,4 @@ function Base.replace_in_print_matrix(A::HermOrSym,i::Integer,j::Integer,s::Abst
     ijminmax = minmax(i, j)
     inds = A.uplo == 'U' ? ijminmax : reverse(ijminmax)
     Base.replace_in_print_matrix(parent(A), inds..., s)
-end
+end

test/symmetric.jl

@@ -1037,10 +1037,12 @@ end
     end
     @testset "hermitianpart for numbers" begin
     @test hermitianpart(3 + 4im) == 3
-    @test hermitianpart(5) == 5
+    @test hermitianpart(5) == 5.0
+    @test typeof(hermitianpart(5)) == Float64
     @test hermitianpart(2.5) == 2.5
     @test hermitianpart(-1 + 0im) == -1
-    @test typeof(hermitianpart(3 + 4im)) == Int
+    @test typeof(hermitianpart(3 + 4im)) == 3.0
+    @test typeof(hermitianpart(3 + 4im)) == Float64
     @test typeof(hermitianpart(2.5 + 3im)) == Float64
 end
 end