fillna not working together with column conditions in Pandas DataFrame
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1
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I am trying to fill NaN values in a dataframe column, but only if a condition in another column is met (I'm working with Kaggle Titanic data). For example:
Age Title
0 10 Mr
1 2 Master
2 NaN Master
3 NaN Mr
In this table, I want to replace the NaN in the 'Age' column with a number, but only if the value in the 'Title' column is 'Master', not if it is 'Mr'. So I want to replace the row 2 NaN, not the row 3 NaN.
I'm trying this and don't understand why it doesn't work:
df.loc[df['Title'].str.contains('Master'),'Age'].fillna(some_number,inplace=True)
Can anyone help?
python dataframe null nan data-cleaning
asked Nov 21 at 21:41
Matthew Davies
61
add a comment |
up vote
1
down vote
favorite
I am trying to fill NaN values in a dataframe column, but only if a condition in another column is met (I'm working with Kaggle Titanic data). For example:
Age Title
0 10 Mr
1 2 Master
2 NaN Master
3 NaN Mr
In this table, I want to replace the NaN in the 'Age' column with a number, but only if the value in the 'Title' column is 'Master', not if it is 'Mr'. So I want to replace the row 2 NaN, not the row 3 NaN.
I'm trying this and don't understand why it doesn't work:
df.loc[df['Title'].str.contains('Master'),'Age'].fillna(some_number,inplace=True)
Can anyone help?
python dataframe null nan data-cleaning
asked Nov 21 at 21:41
Matthew Davies
61
1
what error do you get?
– ehacinom
Nov 21 at 21:49
Hi. Sorry, should have mentioned that. I don't get an error, it just does nothing and the NaN values do not get replaced.
– Matthew Davies
Nov 22 at 6:40
OK, so this works: df.loc[(df['Title'].str.contains('Master'))&(df['Age'].isnull()),'Age']=some_number. But I still don't get why my original code does not work.
– Matthew Davies
Nov 22 at 6:54
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I am trying to fill NaN values in a dataframe column, but only if a condition in another column is met (I'm working with Kaggle Titanic data). For example:
Age Title
0 10 Mr
1 2 Master
2 NaN Master
3 NaN Mr
In this table, I want to replace the NaN in the 'Age' column with a number, but only if the value in the 'Title' column is 'Master', not if it is 'Mr'. So I want to replace the row 2 NaN, not the row 3 NaN.
I'm trying this and don't understand why it doesn't work:
df.loc[df['Title'].str.contains('Master'),'Age'].fillna(some_number,inplace=True)
Can anyone help?
python dataframe null nan data-cleaning
asked Nov 21 at 21:41
Matthew Davies
61
I am trying to fill NaN values in a dataframe column, but only if a condition in another column is met (I'm working with Kaggle Titanic data). For example:
Age Title
0 10 Mr
1 2 Master
2 NaN Master
3 NaN Mr
In this table, I want to replace the NaN in the 'Age' column with a number, but only if the value in the 'Title' column is 'Master', not if it is 'Mr'. So I want to replace the row 2 NaN, not the row 3 NaN.
I'm trying this and don't understand why it doesn't work:
df.loc[df['Title'].str.contains('Master'),'Age'].fillna(some_number,inplace=True)
Can anyone help?
python dataframe null nan data-cleaning
python dataframe null nan data-cleaning
asked Nov 21 at 21:41
Matthew Davies
61
asked Nov 21 at 21:41
Matthew Davies
61
asked Nov 21 at 21:41
Matthew Davies
61
asked Nov 21 at 21:41
Matthew Davies
61
asked Nov 21 at 21:41
Matthew Davies
61
61
1
what error do you get?
– ehacinom
Nov 21 at 21:49
Hi. Sorry, should have mentioned that. I don't get an error, it just does nothing and the NaN values do not get replaced.
– Matthew Davies
Nov 22 at 6:40
OK, so this works: df.loc[(df['Title'].str.contains('Master'))&(df['Age'].isnull()),'Age']=some_number. But I still don't get why my original code does not work.
– Matthew Davies
Nov 22 at 6:54
add a comment |
1
what error do you get?
– ehacinom
Nov 21 at 21:49
Hi. Sorry, should have mentioned that. I don't get an error, it just does nothing and the NaN values do not get replaced.
– Matthew Davies
Nov 22 at 6:40
OK, so this works: df.loc[(df['Title'].str.contains('Master'))&(df['Age'].isnull()),'Age']=some_number. But I still don't get why my original code does not work.
– Matthew Davies
Nov 22 at 6:54
1
1
what error do you get?
– ehacinom
Nov 21 at 21:49
what error do you get?
– ehacinom
Nov 21 at 21:49
Hi. Sorry, should have mentioned that. I don't get an error, it just does nothing and the NaN values do not get replaced.
– Matthew Davies
Nov 22 at 6:40
Hi. Sorry, should have mentioned that. I don't get an error, it just does nothing and the NaN values do not get replaced.
– Matthew Davies
Nov 22 at 6:40
OK, so this works: df.loc[(df['Title'].str.contains('Master'))&(df['Age'].isnull()),'Age']=some_number. But I still don't get why my original code does not work.
– Matthew Davies
Nov 22 at 6:54
OK, so this works: df.loc[(df['Title'].str.contains('Master'))&(df['Age'].isnull()),'Age']=some_number. But I still don't get why my original code does not work.
– Matthew Davies
Nov 22 at 6:54
add a comment |
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1
what error do you get?
– ehacinom
Nov 21 at 21:49
Hi. Sorry, should have mentioned that. I don't get an error, it just does nothing and the NaN values do not get replaced.
– Matthew Davies
Nov 22 at 6:40
OK, so this works: df.loc[(df['Title'].str.contains('Master'))&(df['Age'].isnull()),'Age']=some_number. But I still don't get why my original code does not work.
– Matthew Davies
Nov 22 at 6:54