df.fillna() not working but df.dropna() working





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In my code the df.fillna() method is not working when the df.dropna() method is working. I don't want to drop the column though. What can I do that the fillna() method works?



def preprocess_df(df):
for col in df.columns: # go through all of the columns
if col != "target": # normalize all ... except for the target itself!
df[col] = df[col].pct_change() # pct change "normalizes" the different currencies (each crypto coin has vastly diff values, we're really more interested in the other coin's movements)
# df.dropna(inplace=True) # remove the nas created by pct_change
df.fillna(method="ffill", inplace=True)
print(df)
break
df[col] = preprocessing.scale(df[col].values) # scale between 0 and 1.









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  • Try df.fillna(method="ffill", inplace=True, axis=1)

    – roganjosh
    Nov 22 '18 at 14:16






  • 3





    What do you mean by "not working"? Are you getting an error? If so, what's the error message?

    – Lukas Thaler
    Nov 22 '18 at 14:16











  • the NaN does not disappear.

    – user9468014
    Nov 22 '18 at 14:18













  • I've tried with df.fillna(method="ffill", inplace=True, axis=1) but still the same.

    – user9468014
    Nov 22 '18 at 14:18











  • Error message is: ValueError: Input contains NaN, infinity or a value too large for dtype('float64').

    – user9468014
    Nov 22 '18 at 14:20


















0















In my code the df.fillna() method is not working when the df.dropna() method is working. I don't want to drop the column though. What can I do that the fillna() method works?



def preprocess_df(df):
for col in df.columns: # go through all of the columns
if col != "target": # normalize all ... except for the target itself!
df[col] = df[col].pct_change() # pct change "normalizes" the different currencies (each crypto coin has vastly diff values, we're really more interested in the other coin's movements)
# df.dropna(inplace=True) # remove the nas created by pct_change
df.fillna(method="ffill", inplace=True)
print(df)
break
df[col] = preprocessing.scale(df[col].values) # scale between 0 and 1.









share|improve this question























  • Try df.fillna(method="ffill", inplace=True, axis=1)

    – roganjosh
    Nov 22 '18 at 14:16






  • 3





    What do you mean by "not working"? Are you getting an error? If so, what's the error message?

    – Lukas Thaler
    Nov 22 '18 at 14:16











  • the NaN does not disappear.

    – user9468014
    Nov 22 '18 at 14:18













  • I've tried with df.fillna(method="ffill", inplace=True, axis=1) but still the same.

    – user9468014
    Nov 22 '18 at 14:18











  • Error message is: ValueError: Input contains NaN, infinity or a value too large for dtype('float64').

    – user9468014
    Nov 22 '18 at 14:20














0












0








0


0






In my code the df.fillna() method is not working when the df.dropna() method is working. I don't want to drop the column though. What can I do that the fillna() method works?



def preprocess_df(df):
for col in df.columns: # go through all of the columns
if col != "target": # normalize all ... except for the target itself!
df[col] = df[col].pct_change() # pct change "normalizes" the different currencies (each crypto coin has vastly diff values, we're really more interested in the other coin's movements)
# df.dropna(inplace=True) # remove the nas created by pct_change
df.fillna(method="ffill", inplace=True)
print(df)
break
df[col] = preprocessing.scale(df[col].values) # scale between 0 and 1.









share|improve this question














In my code the df.fillna() method is not working when the df.dropna() method is working. I don't want to drop the column though. What can I do that the fillna() method works?



def preprocess_df(df):
for col in df.columns: # go through all of the columns
if col != "target": # normalize all ... except for the target itself!
df[col] = df[col].pct_change() # pct change "normalizes" the different currencies (each crypto coin has vastly diff values, we're really more interested in the other coin's movements)
# df.dropna(inplace=True) # remove the nas created by pct_change
df.fillna(method="ffill", inplace=True)
print(df)
break
df[col] = preprocessing.scale(df[col].values) # scale between 0 and 1.






python pandas






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asked Nov 22 '18 at 14:11









user9468014user9468014

5110




5110













  • Try df.fillna(method="ffill", inplace=True, axis=1)

    – roganjosh
    Nov 22 '18 at 14:16






  • 3





    What do you mean by "not working"? Are you getting an error? If so, what's the error message?

    – Lukas Thaler
    Nov 22 '18 at 14:16











  • the NaN does not disappear.

    – user9468014
    Nov 22 '18 at 14:18













  • I've tried with df.fillna(method="ffill", inplace=True, axis=1) but still the same.

    – user9468014
    Nov 22 '18 at 14:18











  • Error message is: ValueError: Input contains NaN, infinity or a value too large for dtype('float64').

    – user9468014
    Nov 22 '18 at 14:20



















  • Try df.fillna(method="ffill", inplace=True, axis=1)

    – roganjosh
    Nov 22 '18 at 14:16






  • 3





    What do you mean by "not working"? Are you getting an error? If so, what's the error message?

    – Lukas Thaler
    Nov 22 '18 at 14:16











  • the NaN does not disappear.

    – user9468014
    Nov 22 '18 at 14:18













  • I've tried with df.fillna(method="ffill", inplace=True, axis=1) but still the same.

    – user9468014
    Nov 22 '18 at 14:18











  • Error message is: ValueError: Input contains NaN, infinity or a value too large for dtype('float64').

    – user9468014
    Nov 22 '18 at 14:20

















Try df.fillna(method="ffill", inplace=True, axis=1)

– roganjosh
Nov 22 '18 at 14:16





Try df.fillna(method="ffill", inplace=True, axis=1)

– roganjosh
Nov 22 '18 at 14:16




3




3





What do you mean by "not working"? Are you getting an error? If so, what's the error message?

– Lukas Thaler
Nov 22 '18 at 14:16





What do you mean by "not working"? Are you getting an error? If so, what's the error message?

– Lukas Thaler
Nov 22 '18 at 14:16













the NaN does not disappear.

– user9468014
Nov 22 '18 at 14:18







the NaN does not disappear.

– user9468014
Nov 22 '18 at 14:18















I've tried with df.fillna(method="ffill", inplace=True, axis=1) but still the same.

– user9468014
Nov 22 '18 at 14:18





I've tried with df.fillna(method="ffill", inplace=True, axis=1) but still the same.

– user9468014
Nov 22 '18 at 14:18













Error message is: ValueError: Input contains NaN, infinity or a value too large for dtype('float64').

– user9468014
Nov 22 '18 at 14:20





Error message is: ValueError: Input contains NaN, infinity or a value too large for dtype('float64').

– user9468014
Nov 22 '18 at 14:20












1 Answer
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You were almost there:



df = df.fillna(method="ffill", inplace=True)


You have to assign it back to df






share|improve this answer



















  • 3





    This is incorrect. You should not assign back when you use inplace=True.

    – jpp
    Nov 22 '18 at 15:09











  • not working unfortunetally :(

    – user9468014
    Nov 22 '18 at 22:45











  • My bad @jpp, you are correct. Maybe it is something to do with method='ffill'? According to pd docs, ffill propagates the last valid observation. What if the entire column is NaN s. How does it know what to propagate it with? Perhaps its worth manually telling it what to fill the NaNs with?

    – erncyp
    Nov 23 '18 at 9:15












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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0














You were almost there:



df = df.fillna(method="ffill", inplace=True)


You have to assign it back to df






share|improve this answer



















  • 3





    This is incorrect. You should not assign back when you use inplace=True.

    – jpp
    Nov 22 '18 at 15:09











  • not working unfortunetally :(

    – user9468014
    Nov 22 '18 at 22:45











  • My bad @jpp, you are correct. Maybe it is something to do with method='ffill'? According to pd docs, ffill propagates the last valid observation. What if the entire column is NaN s. How does it know what to propagate it with? Perhaps its worth manually telling it what to fill the NaNs with?

    – erncyp
    Nov 23 '18 at 9:15
















0














You were almost there:



df = df.fillna(method="ffill", inplace=True)


You have to assign it back to df






share|improve this answer



















  • 3





    This is incorrect. You should not assign back when you use inplace=True.

    – jpp
    Nov 22 '18 at 15:09











  • not working unfortunetally :(

    – user9468014
    Nov 22 '18 at 22:45











  • My bad @jpp, you are correct. Maybe it is something to do with method='ffill'? According to pd docs, ffill propagates the last valid observation. What if the entire column is NaN s. How does it know what to propagate it with? Perhaps its worth manually telling it what to fill the NaNs with?

    – erncyp
    Nov 23 '18 at 9:15














0












0








0







You were almost there:



df = df.fillna(method="ffill", inplace=True)


You have to assign it back to df






share|improve this answer













You were almost there:



df = df.fillna(method="ffill", inplace=True)


You have to assign it back to df







share|improve this answer












share|improve this answer



share|improve this answer










answered Nov 22 '18 at 15:01









erncyperncyp

336311




336311








  • 3





    This is incorrect. You should not assign back when you use inplace=True.

    – jpp
    Nov 22 '18 at 15:09











  • not working unfortunetally :(

    – user9468014
    Nov 22 '18 at 22:45











  • My bad @jpp, you are correct. Maybe it is something to do with method='ffill'? According to pd docs, ffill propagates the last valid observation. What if the entire column is NaN s. How does it know what to propagate it with? Perhaps its worth manually telling it what to fill the NaNs with?

    – erncyp
    Nov 23 '18 at 9:15














  • 3





    This is incorrect. You should not assign back when you use inplace=True.

    – jpp
    Nov 22 '18 at 15:09











  • not working unfortunetally :(

    – user9468014
    Nov 22 '18 at 22:45











  • My bad @jpp, you are correct. Maybe it is something to do with method='ffill'? According to pd docs, ffill propagates the last valid observation. What if the entire column is NaN s. How does it know what to propagate it with? Perhaps its worth manually telling it what to fill the NaNs with?

    – erncyp
    Nov 23 '18 at 9:15








3




3





This is incorrect. You should not assign back when you use inplace=True.

– jpp
Nov 22 '18 at 15:09





This is incorrect. You should not assign back when you use inplace=True.

– jpp
Nov 22 '18 at 15:09













not working unfortunetally :(

– user9468014
Nov 22 '18 at 22:45





not working unfortunetally :(

– user9468014
Nov 22 '18 at 22:45













My bad @jpp, you are correct. Maybe it is something to do with method='ffill'? According to pd docs, ffill propagates the last valid observation. What if the entire column is NaN s. How does it know what to propagate it with? Perhaps its worth manually telling it what to fill the NaNs with?

– erncyp
Nov 23 '18 at 9:15





My bad @jpp, you are correct. Maybe it is something to do with method='ffill'? According to pd docs, ffill propagates the last valid observation. What if the entire column is NaN s. How does it know what to propagate it with? Perhaps its worth manually telling it what to fill the NaNs with?

– erncyp
Nov 23 '18 at 9:15




















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