如何在Julia中对GLM预测结果进行舍入

Question

我试图在朱莉娅做一个非常简单的逻辑回归。但是朱莉娅的打字系统似乎给我带来了问题。基本上，glm预测给了我一系列的可能性。我想做一个简单的循环，如果概率>=0.5，它是1，否则是0。我希望这些标签也是整数。

using DataFrames;
using GLM;

df = readtable("./data/titanic-dataset.csv");

delete!(df, :PassengerId);
delete!(df, :Name);
delete!(df, :Ticket);
delete!(df, :Cabin);
pool!(df, [:Sex]);
pool!(df, [:Embarked]);
df[isna.(df[:Age]),:Age] = median(df[ .~isna.(df[:Age]),:Age])

model = glm(@formula(Survived ~ Pclass + Sex + Age + SibSp + Parch + Fare + Embarked), df, Binomial(), LogitLink());
pred = predict(model,df);

z = DataArray([1.0,2.0,3.0]);
println(typeof(z));
println(typeof(pred));
println(round.(Int64,z));  # Why does this work?
println(round.(Int64,pred)); # But this does not?

DataArrays.DataArray{Float64,1}
DataArrays.DataArray{Float64,1}
[1, 2, 3]
MethodError: no method matching round(::Type{Int64}, ::DataArrays.NAtype)
Closest candidates are:
  round(::Type{T<:Integer}, ::Integer) where T<:Integer at int.jl:408
  round(::Type{T<:Integer}, ::Float16) where T<:Integer at float.jl:338
  round(::Type{T<:Union{Signed, Unsigned}}, ::BigFloat) where T<:Union{Signed, Unsigned} at mpfr.jl:214
  ...

Stacktrace:
 [1] macro expansion at C:\Users\JHeaton\.julia\v0.6\DataArrays\src\broadcast.jl:32 [inlined]
 [2] macro expansion at .\cartesian.jl:64 [inlined]
 [3] macro expansion at C:\Users\JHeaton\.julia\v0.6\DataArrays\src\broadcast.jl:111 [inlined]
 [4] _broadcast!(::DataArrays.##116#117{Int64,Base.#round}, ::DataArrays.DataArray{Int64,1}, ::DataArrays.DataArray{Float64,1}) at C:\Users\JHeaton\.julia\v0.6\DataArrays\src\broadcast.jl:67
 [5] broadcast!(::Function, ::DataArrays.DataArray{Int64,1}, ::Type{Int64}, ::DataArrays.DataArray{Float64,1}) at C:\Users\JHeaton\.julia\v0.6\DataArrays\src\broadcast.jl:169
 [6] broadcast(::Function, ::Type{T} where T, ::DataArrays.DataArray{Float64,1}) at .\broadcast.jl:434
 [7] include_string(::String, ::String) at .\loading.jl:515

Answer 1

当z中有nas时，不能创建整数。您可以round.（在这种情况下，您将获得floats的dataarray)，但是当您试图使它们int时，它会抱怨，因为na不能是int64。取而代之的是

convert(DataArray{Int}, round.(z))

此外，使用包中的可用数据而不是计算机上的本地数据集发布示例会更好。