Drop rows by index from dataframe

Change it to

df_train.drop(wrong_indexes_train,axis=1)

Not 100% certain what you want without a minimum-(not)working-example, but you should specify an axis parameter. df.drop returns the modified DataFrame. If you want to operate inplace, specify inplace=True.

See this for symbolic row names (index):

df = pd.DataFrame({"ones":[1,3,5],
                   "tens":[20, 40, 60]},
                  index=['barb', 'mark', 'ethan'])
df.drop(['barb', 'mark'], axis='index')

And this for numeric (default) indices:

df = pd.DataFrame({"ones":[1,3,5],
                   "tens":[20, 40, 60]})
df.drop([0,2], axis='index')