# ScikitLearn.jl "Pycall.jlwrap" error

**URL:** <https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651>\
**Category:** New to Julia\
**Created:** [December 14, 2018, 9:51am UTC](https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651 "2018-12-14T09:51:24Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Rohan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rohan/32/6202_2.png) [@Rohan](https://discourse.julialang.org/u/Rohan)\
**Post date:** [December 14, 2018, 9:51am UTC](https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651/1 "2018-12-14T09:51:24Z")

</div>

Hallo guys,

Newbie here… I am testing ScikitLearn.jl and want to run a simple logistical regression for fun. Following the model API [documentaiton](https://scikitlearnjl.readthedocs.io/en/latest/quickstart/) of ScikitLearn.jl, I got the follwing error after running the code:

```julia
# All of my data here.
# X = Features = Array{Union{Missing, Float64},2}
# y = Label = Array{Union{Missing, Int64},2}

#ScikitLearn
@sk_import linear_model: LogisticRegression
model = LogisticRegression(fit_intercept=true)

#Fit data
fit!(model, Features, Label)

```

I got the TypeError below:

```julia
PyError ($(Expr(:escape, :(ccall(#= C:\Users\posthumusjj\.juliapro\packages\PyCall\0jMpb\src\pyfncall.jl:44 =# @pysym(:PyObject_Call), PyPtr, (PyPtr, PyPtr, PyPtr), o, pyargsptr, kw))))) <class 'TypeError'>
TypeError("float() argument must be a string or a number, not 'PyCall.jlwrap'",)
  File "C:\Users\posthumusjj\.juliapro\packages\Conda\hsaaN\deps\usr\lib\site-packages\sklearn\linear_model\logistic.py", line 1285, in fit
    accept_large_sparse=solver != 'liblinear')
  File "C:\Users\posthumusjj\.juliapro\packages\Conda\hsaaN\deps\usr\lib\site-packages\sklearn\utils\validation.py", line 756, in check_X_y
    estimator=estimator)
  File "C:\Users\posthumusjj\.juliapro\packages\Conda\hsaaN\deps\usr\lib\site-packages\sklearn\utils\validation.py", line 527, in check_array
    array = np.asarray(array, dtype=dtype, order=order)
  File "C:\Users\posthumusjj\.juliapro\packages\Conda\hsaaN\deps\usr\lib\site-packages\numpy\core\numeric.py", line 501, in asarray
    return array(a, dtype, copy=False, order=order)
in top-level scope at base\none
in fit! at ScikitLearn\HK6Vs\src\Skcore.jl:100
in #fit!#26 at ScikitLearn\HK6Vs\src\Skcore.jl:100
in at PyCall\0jMpb\src\pyfncall.jl:89
in #call#89 at PyCall\0jMpb\src\pyfncall.jl:89
in _pycall! at PyCall\0jMpb\src\pyfncall.jl:11
in _pycall! at PyCall\0jMpb\src\pyfncall.jl:22
in __pycall! at PyCall\0jMpb\src\pyfncall.jl:44
in macro expansion at PyCall\0jMpb\src\exception.jl:84 
in pyerr_check at PyCall\0jMpb\src\exception.jl:64 
in pyerr_check at PyCall\0jMpb\src\exception.jl:60 
PyError ($(Expr(:escape, :(ccall(#= C:\Users\posthumusjj\.juliapro\packages\PyCall\0jMpb\src\pyfncall.jl:44 =# @pysym(:PyObject_Call), PyPtr, (PyPtr, PyPtr, PyPtr), o, pyargsptr, kw))))) <class 'sklearn.exceptions.NotFittedError'>

PyObject LogisticRegression(C=1.0, class_weight=None, dual=False, fit_intercept=True,
REPL

```

How do I call values instead of the object?

Thanks in advance

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**Author:** ![cstjean](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cstjean/32/1444_2.png) [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Post date:** [December 14, 2018, 2:52pm UTC](https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651/2 "2018-12-14T14:52:08Z")

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ScikitLearn maintainer here. I don’t think I’ve ever tested `missing` values. I’d have to think about how best to handle them. If you take out the rows with `missing`s, does it work?

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**Author:** ![Rohan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rohan/32/6202_2.png) [@Rohan](https://discourse.julialang.org/u/Rohan)\
**Post date:** [December 18, 2018, 6:13pm UTC](https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651/3 "2018-12-18T18:13:52Z")

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Oh, so if I understand correct, the missing values does not pass through and then the PyObject causes the TypeError?

Our research group is now closed for the holidays and I don’t have access to the data until January. Will run it then again without missings.

Thanx!

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<div class="post-metadata">

**Author:** ![cstjean](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/cstjean/32/1444_2.png) [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Post date:** [December 18, 2018, 6:59pm UTC](https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651/4 "2018-12-18T18:59:31Z")

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Yeah. ScikitLearn.jl just passes the data to Python via PyCall here, and Python does not have a `missing` type, so there’s nothing PyCall can do besides an error, I believe. You should filter out the rows with `missing`, if that’s possible. Or maybe try turning them into NaNs?

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**Author:** ![tkf](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tkf/32/17635_2.png) [@tkf](https://discourse.julialang.org/u/tkf)\
**Post date:** [December 18, 2018, 7:11pm UTC](https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651/5 "2018-12-18T19:11:30Z")

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For `Array{Union{Missing, T}}` where `T` is supported by Numpy, it may make sense to convert it to a [`numpy.ma.MaskedArray`](https://docs.scipy.org/doc/numpy/reference/maskedarray.html). But I don’t know if it can be done in a copy-free manner like for `Array{T}`.

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<div class="post-metadata">

**Author:** ![Rohan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rohan/32/6202_2.png) [@Rohan](https://discourse.julialang.org/u/Rohan)\
**Post date:** [December 18, 2018, 8:11pm UTC](https://discourse.julialang.org/t/scikitlearn-jl-pycall-jlwrap-error/18651/6 "2018-12-18T20:11:09Z")

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I didn’t even think of removing the missing values since the software I currently use automatically handles it. I’ll look for Julia’s version of Pandas dropna().