Hello,

I am trying to write a loop for a logistic regession. I have a dataframe with about 20 columns and I would like to use one of the columns after each other and print the coeftable afterwards. In the end I am aiming to make a stepwise logistic regression.

I’ve got this example code which performs well:

```
using DataFrames, GLM
srand(42)
df_test = DataFrame(A = rand(Int, 100), B = rand(Int, 100), C = rand(0:1, 100) )
model_test = glm(@formula(C ~ A + B),
df_test, Binomial(), LogitLink())
println(coeftable(model_test))
```

But I would like to get all the column names (df_names) and than tell the model to use this names as an input (df_names[1]):

```
df_names = names(df_test)
model_test = glm(@formula(C ~ df_names[1] + df_names[2]),
df_test, Binomial(), LogitLink())
```

when I execute the code I get this error message:

```
Non-call expression encountered
in glm at GLM\src\glmfit.jl:286
in #glm#13 at GLM\src\glmfit.jl:286
in fit at DataFrames\src\statsmodels\statsmodel.jl:52
in #fit#153 at DataFrames\src\statsmodels\statsmodel.jl:52
in at base\<missing>
in #ModelFrame#127 at DataFrames\src\statsmodels\formula.jl:333
in DataFrames.Terms at DataFrames\src\statsmodels\formula.jl:209
in dospecials at DataFrames\src\statsmodels\formula.jl:101
in map at base\abstractarray.jl:1868
in _collect at base\array.jl:488
in next at base\generator.jl:45
in dospecials at DataFrames\src\statsmodels\formula.jl:97
```

so I would like to make df_names[1] callable. Does anybody has a suggestion how to make it callable?

And does anybody has an idea how to performe a stepwise logistic regression?

Cheers!

Tobi