Python: Logistic Regression gives ValueError: Unknown label type: 'continuous'

Question

I have a question related to Logistic Regression where I am getting ValueError

Here's my dataset:

             sub1         sub2              sub3       sub4
pol_1     0.000000      0.000000            0.0      0.000000   
pol_2     0.000000      0.000000            0.0      0.000000   
pol_3     0.050000      0.000000            0.0      0.000000   
pol_4     0.000000      0.000000            0.0      0.000000   
pol_5     0.000000      0.000000            0.0      0.000000   
pol_6     0.000000      0.000000            0.0      0.000000   
pol_7     0.000000      0.000000            0.0      0.000000   
pol_8     0.000000      0.000000            0.0      0.000000   
pol_9     0.000000      0.000000            0.0      0.000000   
pol_10    0.000000      0.000000            0.0      0.032423   
pol_11    0.000000      0.000000            0.0      0.000000   
pol_12    0.000000      0.000000            0.0      0.000000   
pol_13    0.000000      0.000000            0.0      0.000000   
pol_14    0.000000      0.053543            0.0      0.000000   
pol_15    0.000000      0.000000            0.0      0.000000   
pol_16    0.000000      0.000000            0.0      0.000000   
pol_17    0.000000      0.000000            0.0      0.000000   
pol_18    0.000000      0.000000            0.0      0.053453   
pol_19    0.000000      0.058344            0.0      0.000000   
pol_20    0.054677      0.000000            0.0      0.000000

This is my code:

array = df.values
X = array[:,0:3]
Y = array[:,3]
validation_size = 0.20
seed = 7
X_train, X_validation, Y_train, Y_validation = 
model_selection.train_test_split(X, Y, test_size=validation_size, 
random_state=seed)

seed = 7
scoring = 'accuracy'

kfold = model_selection.KFold(n_splits=10, random_state=seed)
cv_results = model_selection.cross_val_score(LogisticRegression(), X_train, Y_train, cv=kfold, scoring=scoring)
print(cv_results)

This gives me the following error:

ValueError: Unknown label type: 'continuous'

How can this issue be tackled?

Also, I looked through certain links and found that the issue could be related to datatype which in my case is:

print(df.dtypes)
print(X_train.dtype)

pol_1     float64
pol_2     float64
pol_3     float64
pol_4     float64
pol_5     float64
pol_6     float64
pol_7     float64
pol_8     float64
pol_9     float64
pol_10    float64
pol_11    float64
pol_12    float64
pol_13    float64
pol_14    float64
pol_15    float64
pol_16    float64
pol_17    float64
pol_18    float64
pol_19    float64
pol_20    float64
Length: 20, dtype: object
float64

I tried to convert the datatype for X_train and Y_train to string but got the same error.

Thanks!

Answer 1

The type of Y should be int. That is, it should consist of integers that represent the class labels. However, in your data frame the Y column consists of floats, and hence you get this error.