'generator' object is not callable when if inside a for loop in list compression












0














I am getting the following error when i ran this:



df['initial_referrer'].apply(lambda x: value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&'))



TypeError: 'generator' object is not callable




I am not sure the meaning of the error and how to modify my this to get rid of this. I have read couple of similar questions here but could not figure our what could be the issue.



So I have values in df['initial_referrer'] be like:



df['initial_referrer'].head()
0 /login/index.php
1 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
2 /login/index.php
3 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
4 /login/index.php


And in this, I wanted to extract the value of utm_campaign which is login-day1 thats why I was using the for loop and then if statement it was taking a lot of time/days to process 20mil rows. Therefore I wanted to use generator expression or list compression to process it faster.










share|improve this question




















  • 1




    you're not using a list-comprehension, you are using a generator expression
    – juanpa.arrivillaga
    Nov 12 '18 at 10:25










  • Basically I was doing this using itterrows earlier but it was taking a lot of time so I thought of doing this using apply
    – Gagan
    Nov 12 '18 at 10:28










  • use itertuples. But .apply isn't going to be much faster. It's basically a plain python for-loop underneath the hood
    – juanpa.arrivillaga
    Nov 12 '18 at 10:28










  • If you'd extract a Minimal, Complete, and Verifiable example, you might find the error yourself. Also, it would make this question much more valuable to others.
    – Ulrich Eckhardt
    Nov 12 '18 at 10:39










  • @UlrichEckhardt let me know if question make sense now. I dont think downvote would solve the purpose though but anyways.
    – Gagan
    Nov 12 '18 at 10:44
















0














I am getting the following error when i ran this:



df['initial_referrer'].apply(lambda x: value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&'))



TypeError: 'generator' object is not callable




I am not sure the meaning of the error and how to modify my this to get rid of this. I have read couple of similar questions here but could not figure our what could be the issue.



So I have values in df['initial_referrer'] be like:



df['initial_referrer'].head()
0 /login/index.php
1 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
2 /login/index.php
3 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
4 /login/index.php


And in this, I wanted to extract the value of utm_campaign which is login-day1 thats why I was using the for loop and then if statement it was taking a lot of time/days to process 20mil rows. Therefore I wanted to use generator expression or list compression to process it faster.










share|improve this question




















  • 1




    you're not using a list-comprehension, you are using a generator expression
    – juanpa.arrivillaga
    Nov 12 '18 at 10:25










  • Basically I was doing this using itterrows earlier but it was taking a lot of time so I thought of doing this using apply
    – Gagan
    Nov 12 '18 at 10:28










  • use itertuples. But .apply isn't going to be much faster. It's basically a plain python for-loop underneath the hood
    – juanpa.arrivillaga
    Nov 12 '18 at 10:28










  • If you'd extract a Minimal, Complete, and Verifiable example, you might find the error yourself. Also, it would make this question much more valuable to others.
    – Ulrich Eckhardt
    Nov 12 '18 at 10:39










  • @UlrichEckhardt let me know if question make sense now. I dont think downvote would solve the purpose though but anyways.
    – Gagan
    Nov 12 '18 at 10:44














0












0








0


0





I am getting the following error when i ran this:



df['initial_referrer'].apply(lambda x: value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&'))



TypeError: 'generator' object is not callable




I am not sure the meaning of the error and how to modify my this to get rid of this. I have read couple of similar questions here but could not figure our what could be the issue.



So I have values in df['initial_referrer'] be like:



df['initial_referrer'].head()
0 /login/index.php
1 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
2 /login/index.php
3 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
4 /login/index.php


And in this, I wanted to extract the value of utm_campaign which is login-day1 thats why I was using the for loop and then if statement it was taking a lot of time/days to process 20mil rows. Therefore I wanted to use generator expression or list compression to process it faster.










share|improve this question















I am getting the following error when i ran this:



df['initial_referrer'].apply(lambda x: value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&'))



TypeError: 'generator' object is not callable




I am not sure the meaning of the error and how to modify my this to get rid of this. I have read couple of similar questions here but could not figure our what could be the issue.



So I have values in df['initial_referrer'] be like:



df['initial_referrer'].head()
0 /login/index.php
1 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
2 /login/index.php
3 /login/index.php?utm_source=INTERNAL&utm_medium=EMAIL&utm_campaign=login-day1
4 /login/index.php


And in this, I wanted to extract the value of utm_campaign which is login-day1 thats why I was using the for loop and then if statement it was taking a lot of time/days to process 20mil rows. Therefore I wanted to use generator expression or list compression to process it faster.







python pandas performance






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 12 '18 at 11:31









jpp

91.9k2052102




91.9k2052102










asked Nov 12 '18 at 10:23









Gagan

392520




392520








  • 1




    you're not using a list-comprehension, you are using a generator expression
    – juanpa.arrivillaga
    Nov 12 '18 at 10:25










  • Basically I was doing this using itterrows earlier but it was taking a lot of time so I thought of doing this using apply
    – Gagan
    Nov 12 '18 at 10:28










  • use itertuples. But .apply isn't going to be much faster. It's basically a plain python for-loop underneath the hood
    – juanpa.arrivillaga
    Nov 12 '18 at 10:28










  • If you'd extract a Minimal, Complete, and Verifiable example, you might find the error yourself. Also, it would make this question much more valuable to others.
    – Ulrich Eckhardt
    Nov 12 '18 at 10:39










  • @UlrichEckhardt let me know if question make sense now. I dont think downvote would solve the purpose though but anyways.
    – Gagan
    Nov 12 '18 at 10:44














  • 1




    you're not using a list-comprehension, you are using a generator expression
    – juanpa.arrivillaga
    Nov 12 '18 at 10:25










  • Basically I was doing this using itterrows earlier but it was taking a lot of time so I thought of doing this using apply
    – Gagan
    Nov 12 '18 at 10:28










  • use itertuples. But .apply isn't going to be much faster. It's basically a plain python for-loop underneath the hood
    – juanpa.arrivillaga
    Nov 12 '18 at 10:28










  • If you'd extract a Minimal, Complete, and Verifiable example, you might find the error yourself. Also, it would make this question much more valuable to others.
    – Ulrich Eckhardt
    Nov 12 '18 at 10:39










  • @UlrichEckhardt let me know if question make sense now. I dont think downvote would solve the purpose though but anyways.
    – Gagan
    Nov 12 '18 at 10:44








1




1




you're not using a list-comprehension, you are using a generator expression
– juanpa.arrivillaga
Nov 12 '18 at 10:25




you're not using a list-comprehension, you are using a generator expression
– juanpa.arrivillaga
Nov 12 '18 at 10:25












Basically I was doing this using itterrows earlier but it was taking a lot of time so I thought of doing this using apply
– Gagan
Nov 12 '18 at 10:28




Basically I was doing this using itterrows earlier but it was taking a lot of time so I thought of doing this using apply
– Gagan
Nov 12 '18 at 10:28












use itertuples. But .apply isn't going to be much faster. It's basically a plain python for-loop underneath the hood
– juanpa.arrivillaga
Nov 12 '18 at 10:28




use itertuples. But .apply isn't going to be much faster. It's basically a plain python for-loop underneath the hood
– juanpa.arrivillaga
Nov 12 '18 at 10:28












If you'd extract a Minimal, Complete, and Verifiable example, you might find the error yourself. Also, it would make this question much more valuable to others.
– Ulrich Eckhardt
Nov 12 '18 at 10:39




If you'd extract a Minimal, Complete, and Verifiable example, you might find the error yourself. Also, it would make this question much more valuable to others.
– Ulrich Eckhardt
Nov 12 '18 at 10:39












@UlrichEckhardt let me know if question make sense now. I dont think downvote would solve the purpose though but anyways.
– Gagan
Nov 12 '18 at 10:44




@UlrichEckhardt let me know if question make sense now. I dont think downvote would solve the purpose though but anyways.
– Gagan
Nov 12 '18 at 10:44












1 Answer
1






active

oldest

votes


















5














It's instructive to first use apply with a regular function:



def func(x):
return [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan
for value in x.split('&')]

df['initial_referrer'].apply(func)


Notice the square brackets representing the list comprehension. You need to translate this to your lambda function:



df['initial_referrer'].apply(lambda x: [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&')])


But the latter is unreadable. You are better off writing a regular function.



Note pd.Series.apply is a Python-level loop. You can use map instead and will likely see a performance improvement:



df['initial_referrer'] = list(map(func, df['initial_referrer'].values))


Or even a list comprehension:



df['initial_referrer'] = [func(x) for x in df['initial_referrer'].values]





share|improve this answer























  • Thanks jpp. any particular idea which way would be faster? I have 20mil rows to process
    – Gagan
    Nov 12 '18 at 10:32












  • @Gagan, See my last 2 suggestions. Test them and time to see what's most efficient.
    – jpp
    Nov 12 '18 at 10:33










  • Thanks @jpp, I changed the function to this: def func(x): return [value.split("utm_campaign=",1)[1] for value in x.split('&') if 'utm_campaign' in value][0] And statement to this: df['initial_referrer_1'] = [func(x) if 'utm_campaign' in x else np.nan for x in df['initial_referrer'].values]. And it worked.
    – Gagan
    Nov 12 '18 at 11:12











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









5














It's instructive to first use apply with a regular function:



def func(x):
return [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan
for value in x.split('&')]

df['initial_referrer'].apply(func)


Notice the square brackets representing the list comprehension. You need to translate this to your lambda function:



df['initial_referrer'].apply(lambda x: [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&')])


But the latter is unreadable. You are better off writing a regular function.



Note pd.Series.apply is a Python-level loop. You can use map instead and will likely see a performance improvement:



df['initial_referrer'] = list(map(func, df['initial_referrer'].values))


Or even a list comprehension:



df['initial_referrer'] = [func(x) for x in df['initial_referrer'].values]





share|improve this answer























  • Thanks jpp. any particular idea which way would be faster? I have 20mil rows to process
    – Gagan
    Nov 12 '18 at 10:32












  • @Gagan, See my last 2 suggestions. Test them and time to see what's most efficient.
    – jpp
    Nov 12 '18 at 10:33










  • Thanks @jpp, I changed the function to this: def func(x): return [value.split("utm_campaign=",1)[1] for value in x.split('&') if 'utm_campaign' in value][0] And statement to this: df['initial_referrer_1'] = [func(x) if 'utm_campaign' in x else np.nan for x in df['initial_referrer'].values]. And it worked.
    – Gagan
    Nov 12 '18 at 11:12
















5














It's instructive to first use apply with a regular function:



def func(x):
return [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan
for value in x.split('&')]

df['initial_referrer'].apply(func)


Notice the square brackets representing the list comprehension. You need to translate this to your lambda function:



df['initial_referrer'].apply(lambda x: [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&')])


But the latter is unreadable. You are better off writing a regular function.



Note pd.Series.apply is a Python-level loop. You can use map instead and will likely see a performance improvement:



df['initial_referrer'] = list(map(func, df['initial_referrer'].values))


Or even a list comprehension:



df['initial_referrer'] = [func(x) for x in df['initial_referrer'].values]





share|improve this answer























  • Thanks jpp. any particular idea which way would be faster? I have 20mil rows to process
    – Gagan
    Nov 12 '18 at 10:32












  • @Gagan, See my last 2 suggestions. Test them and time to see what's most efficient.
    – jpp
    Nov 12 '18 at 10:33










  • Thanks @jpp, I changed the function to this: def func(x): return [value.split("utm_campaign=",1)[1] for value in x.split('&') if 'utm_campaign' in value][0] And statement to this: df['initial_referrer_1'] = [func(x) if 'utm_campaign' in x else np.nan for x in df['initial_referrer'].values]. And it worked.
    – Gagan
    Nov 12 '18 at 11:12














5












5








5






It's instructive to first use apply with a regular function:



def func(x):
return [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan
for value in x.split('&')]

df['initial_referrer'].apply(func)


Notice the square brackets representing the list comprehension. You need to translate this to your lambda function:



df['initial_referrer'].apply(lambda x: [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&')])


But the latter is unreadable. You are better off writing a regular function.



Note pd.Series.apply is a Python-level loop. You can use map instead and will likely see a performance improvement:



df['initial_referrer'] = list(map(func, df['initial_referrer'].values))


Or even a list comprehension:



df['initial_referrer'] = [func(x) for x in df['initial_referrer'].values]





share|improve this answer














It's instructive to first use apply with a regular function:



def func(x):
return [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan
for value in x.split('&')]

df['initial_referrer'].apply(func)


Notice the square brackets representing the list comprehension. You need to translate this to your lambda function:



df['initial_referrer'].apply(lambda x: [value.split("utm_campaign=",1)[1] if 'utm_campaign' in value else np.nan for value in x.split('&')])


But the latter is unreadable. You are better off writing a regular function.



Note pd.Series.apply is a Python-level loop. You can use map instead and will likely see a performance improvement:



df['initial_referrer'] = list(map(func, df['initial_referrer'].values))


Or even a list comprehension:



df['initial_referrer'] = [func(x) for x in df['initial_referrer'].values]






share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 12 '18 at 10:33

























answered Nov 12 '18 at 10:28









jpp

91.9k2052102




91.9k2052102












  • Thanks jpp. any particular idea which way would be faster? I have 20mil rows to process
    – Gagan
    Nov 12 '18 at 10:32












  • @Gagan, See my last 2 suggestions. Test them and time to see what's most efficient.
    – jpp
    Nov 12 '18 at 10:33










  • Thanks @jpp, I changed the function to this: def func(x): return [value.split("utm_campaign=",1)[1] for value in x.split('&') if 'utm_campaign' in value][0] And statement to this: df['initial_referrer_1'] = [func(x) if 'utm_campaign' in x else np.nan for x in df['initial_referrer'].values]. And it worked.
    – Gagan
    Nov 12 '18 at 11:12


















  • Thanks jpp. any particular idea which way would be faster? I have 20mil rows to process
    – Gagan
    Nov 12 '18 at 10:32












  • @Gagan, See my last 2 suggestions. Test them and time to see what's most efficient.
    – jpp
    Nov 12 '18 at 10:33










  • Thanks @jpp, I changed the function to this: def func(x): return [value.split("utm_campaign=",1)[1] for value in x.split('&') if 'utm_campaign' in value][0] And statement to this: df['initial_referrer_1'] = [func(x) if 'utm_campaign' in x else np.nan for x in df['initial_referrer'].values]. And it worked.
    – Gagan
    Nov 12 '18 at 11:12
















Thanks jpp. any particular idea which way would be faster? I have 20mil rows to process
– Gagan
Nov 12 '18 at 10:32






Thanks jpp. any particular idea which way would be faster? I have 20mil rows to process
– Gagan
Nov 12 '18 at 10:32














@Gagan, See my last 2 suggestions. Test them and time to see what's most efficient.
– jpp
Nov 12 '18 at 10:33




@Gagan, See my last 2 suggestions. Test them and time to see what's most efficient.
– jpp
Nov 12 '18 at 10:33












Thanks @jpp, I changed the function to this: def func(x): return [value.split("utm_campaign=",1)[1] for value in x.split('&') if 'utm_campaign' in value][0] And statement to this: df['initial_referrer_1'] = [func(x) if 'utm_campaign' in x else np.nan for x in df['initial_referrer'].values]. And it worked.
– Gagan
Nov 12 '18 at 11:12




Thanks @jpp, I changed the function to this: def func(x): return [value.split("utm_campaign=",1)[1] for value in x.split('&') if 'utm_campaign' in value][0] And statement to this: df['initial_referrer_1'] = [func(x) if 'utm_campaign' in x else np.nan for x in df['initial_referrer'].values]. And it worked.
– Gagan
Nov 12 '18 at 11:12


















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