'A value is trying to be set on a copy of a slice from a DataFrame' error while using 'iloc'
Jupiter nootbook is returning this warning:
*C:\anaconda\lib\site-packages\pandas\core\indexing.py:337: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
self.obj[key] = _infer_fill_value(value)
C:\anaconda\lib\site-packages\pandas\core\indexing.py:517: SettingWithCopyWarning:
A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
self.obj[item] = s*
After runing the following code:
def group_df(df,num):
ln = len(df)
rang = np.arange(ln)
splt = np.array_split(rang,num)
lst = []
finel_lst = []
for i,x in enumerate(splt):
lst.append([i for x in range(len(x))])
for k in lst:
for j in k:
finel_lst.append(j)
df['group'] = finel_lst
return df
def KNN(dafra,folds,K,fi,target):
df = group_df(dafra,folds)
avarge_e = []
for i in range(folds):
train = df.loc[df['group'] != i]
test = df.loc[df['group'] == i]
test.loc[:,'pred_price'] = np.nan
test.loc[:,'rmse'] = np.nan
print(test.columns)
KNN(data,5,5,'GrLivArea','SalePrice')
In the error message, it is recommended to use .loc
indexing- which i did, but it did not help. Please help me- what is the problem ? I have went through the related questions and read the documentation, but i still don't get it.
I think you need copy
:
train = df.loc[df['group'] != i].copy()
test = df.loc[df['group'] == i].copy()
If you modify values in test
later you will find that the modifications do not propagate back to the original data (df
), and that Pandas does warning.