I'm trying to fill missing data with data found in other fields, for example, I have a table:
Brand Model Make
Toyota Corolla Japan
Toyota Crescida Japan
Toyota Land Cruiser
Ford Escape America
Ford Explorer America
Ford Edge
Ford Focus
I know from other rows that Toyota is from Japan and Ford from America. How can I do this in Pandas to give me the below?
Brand Model Make
Toyota Corolla Japan
Toyota Crescida Japan
Toyota Land Cruiser Japan
Ford Escape America
Ford Explorer America
Ford Edge America
Ford Focus America
You can use df=df1[['Brand','Make']].groupby(['Brand']).agg(lambda x:x.value_counts().index[0]).reset_index() to get the common occurences for the make column on the basis of Brand.
After that you can use the following code
for index,value in enumerate(df1['Make']):
if value==None:
brand=df1['Brand'][index]
df1['Make'][index]=df['Make'][df['Brand']==brand].to_list()[0]
I was able to solve it in two steps:
created another df:
df2 = pd.DataFrame(df.groupby('Brand')['Make'].first())
lookup up Make from df2 to fill original df:
df['Make']=df.Brand.apply(lambda x: df2[df2['Brand']==x]['Make'])
Brand Model Make
0 Toyota Corolla Japan
1 Toyota Crescida Japan
2 Toyota Prado Japan
I have the following Pandas series from the dataframe 'Reducedset':
Reducedset = Top15.iloc[:,10:20].mean(axis=1).sort_values(ascending=False)
Which gives me:
Country
United States 1.536434e+13
China 6.348609e+12
Japan 5.542208e+12
Germany 3.493025e+12
France 2.681725e+12
United Kingdom 2.487907e+12
Brazil 2.189794e+12
Italy 2.120175e+12
India 1.769297e+12
Canada 1.660647e+12
Russian Federation 1.565459e+12
Spain 1.418078e+12
Australia 1.164043e+12
South Korea 1.106715e+12
Iran 4.441558e+11
dtype: float64
I want to update the index, so that index of the dataframe Reducedset is in the same order as the series above.
How can I do this?
In other words, when I then look at the entire dataframe, the index order should be the same as in the series above and not like that below:
Reducedset
Rank Documents Citable documents Citations \
Country
China 1 127050 126767 597237
United States 2 96661 94747 792274
Japan 3 30504 30287 223024
United Kingdom 4 20944 20357 206091
Russian Federation 5 18534 18301 34266
Canada 6 17899 17620 215003
Germany 7 17027 16831 140566
India 8 15005 14841 128763
France 9 13153 12973 130632
South Korea 10 11983 11923 114675
Italy 11 10964 10794 111850
Spain 12 9428 9330 123336
Iran 13 8896 8819 57470
Australia 14 8831 8725 90765
Brazil 15 8668 8596 60702
The answer:
Reducedset = Top15.iloc[:,10:20].mean(axis=1).sort_values(ascending=False)
This first stage finds the mean of columns 10-20 for each row (axis=1) and sorts them in descending order (ascending = False)
Reducedset.reindex(Reducedset.index)
Here, we are resetting the index of the dataframe 'Reducedset' as the index of the amended dataframe above.
I have two df's
df1
date League teams
0 201902272215 brazil cup foz do iguacu fcceara ce
1 201902272300 colombia primera a deportes tolimaatletico bucaramanga
2 201902272300 brazil campeonato gaucho 2nd division ypiranga rsuniao frederiquense
3 201902272300 brazil campeonato gaucho 2nd division esportivo rstupi rs
4 201902272300 brazil campeonato gaucho 2nd division sao paulo rsgremio esportivo bage
14 201902280000 four nations women tournament (in usa) usa (w)japan (w)
25 201902280030 bolivia professional football league real potosibolivar
df2
date league teams
0 201902280000 womens international usa womenjapan women
1 201902280000 brazil amazonense sul america ecrio negro am
2 201902280030 bolivia apertura real potosibolivar
3 201902280030 brazil campeonato paulista palmeirasituano
4 201902280030 copa sudamericana racing clubcorinthians
The result I would want is all the rows from df2 that are near matches with df1
date league teams near_match
0 201902280000 womens international usa womenjapan women 1
1 201902280000 brazil amazonense sul america ecrio negro am 0
2 201902280030 bolivia apertura real potosibolivar 1
3 201902280030 brazil campeonato paulista palmeirasituano 0
4 201902280030 copa sudamericana racing clubcorinthians 0
I have tried to use a variation of a for loop using SequenceMatcher and setting the threshold to a match of above 0.8, but haven't had any luck.
df_1['merge_teams'] = df_1['teams'] # we will use these as the merge keys
df_1['merge_date'] = df_1['date']
# df_1['merge_league'] = df_1['league']
for teams_1, date_1, league_1 in df_1[['teams','date']].values:
for ixb, (teams_1, teams_2) in enumerate(df_2[['teams','date']].values):
if difflib.SequenceMatcher(None,teams_1,teams_2).ratio() > .8:
df_2.ix[ixb,'merge_teams'] = teams_1 # creates a merge key in df_2
if difflib.SequenceMatcher(None,date_1, date_2).ratio() > .8:
df_2.ix[ixb,'merge_date'] = date_1 # creates a merge key in df_2
# This should rturn all rows where teams,date and league all match by over 80%
# This is just for teams and date, I want to include league as well
Any advice or guidance would be greatly appreciated.
I have a dataframe as below:
import pandas as pd
df = pd.DataFrame({'Country':['USA','USA','MEX','IND','UK','UK','UK'],
'Region':['Americas','NaN','NaN','Asia','Europe','NaN','NaN'],
'Flower':['Rose','Rose','Lily','Orchid','Dandelion','Dandelion','Dandelion'],
'Animal':['Bison','NaN','Golden Eagle','Tiger','Lion','Lion','NaN'],
'Game':['Baseball','Baseball','soccer','hockey','cricket','cricket','cricket']})
I want to group by Country and Flower and forward fill or backward fill the columns Region and Animal where there are missing values. However the column Game should remain intact
I have tried this but it didn't work:
df['Region'] = df.groupby(['Country','Flower'])['Region'].transform(lambda x: x.ffill())
also :
df.groupby(['Country','Flower'])['Animal', 'Region'].isna().bfill()
I want to know how to go about with this.
while this works but it removes the Games column:
df=df.replace({'NaN':np.nan})
df.groupby(['Country','Flower'])['Animal', 'Region'].bfill().ffill()
And if i do a transform there is a mismatch in the length. Also please note that this is sample dataframe where I had added "NaN" as a string in the original frame it is as np.nan.
If you change your dataframe code to actually include np.nans, then the code you provided actually works. Although nans appear as normal text 'Nan', you can't create a dataframe writing that text by hand because that will be interpreted as a string, not an actual missing value.
import pandas as pd
import numpy as np
df = pd.DataFrame({'Country':['USA','USA','MEX','IND','UK','UK','UK'],
'Region':['Americas',np.nan,np.nan,'Asia','Europe',np.nan,np.nan],
'Flower':['Rose','Rose','Lily','Orchid','Dandelion','Dandelion','Dandelion'],
'Animal':['Bison',np.nan,'Golden Eagle','Tiger','Lion','Lion','NaN'],
'Game':['Baseball','Baseball','soccer','hockey','cricket','cricket','cricket']})
Then, this:
df['Region'] = df.groupby(['Country','Flower'])['Region'].transform(lambda x: x.ffill())
actually yields this:
Animal Country Flower Game Region
0 Bison USA Rose Baseball Americas
1 NaN USA Rose Baseball Americas
2 Golden Eagle MEX Lily soccer NaN
3 Tiger IND Orchid hockey Asia
4 Lion UK Dandelion cricket Europe
5 Lion UK Dandelion cricket Europe
6 NaN UK Dandelion cricket Europe
First you need to know 'NaN' is not NaN
df=df.replace({'NaN':np.nan})
df.groupby(['Country','Flower'])['Region'].ffill()
Out[109]:
0 Americas
1 Americas
2 NaN# since here only have single row , that why stay NaN
3 Asia
4 Europe
5 Europe
6 Europe
Name: Region, dtype: object
Second if you need to chain two iid function in pandas you need apply
df.update(df.groupby(['Country','Flower'])['Animal', 'Region'].apply(lambda x : x.bfill().ffill()))
df
Out[119]:
Animal Country Flower Game Region
0 Bison USA Rose Baseball Americas
1 Bison USA Rose Baseball Americas
2 Golden Eagle MEX Lily soccer NaN
3 Tiger IND Orchid hockey Asia
4 Lion UK Dandelion cricket Europe
5 Lion UK Dandelion cricket Europe
6 Lion UK Dandelion cricket Europe
As Mex and Lily are only rows and moreover their region value is nan, fillna function not able to find appropriate group value.
If we catch the exception while fillna group mode then those value where there is no group will be left as it is. Then apply ffill and bfill to cover those value which doesn't have appropriate group
df_stack = pd.DataFrame({'Country':['USA','USA','MEX','IND','UK','UK','UK'],'Region': ['Americas',np.nan,np.nan,'Asia','Europe',np.nan,np.nan],'Flower': ['Rose','Rose','Lily','Orchid','Dandelion','Dandelion','Dandelion'],'Animal':['Bison',np.nan,'Golden Eagle','Tiger','Lion','Lion',np.nan],'Game': ['Baseball','Baseball','soccer','hockey','cricket','cricket','cricket']})
print("-------Before imputation------")
print(df_stack)
def fillna_Region(grp):
try:
return grp.fillna(grp.mode()[0])
except BaseException as e:
print('Error as no correspindg group: ' + str(e))
df_stack["Region"] =
df_stack["Region"].fillna(df_stack.groupby(['Country','Flower']) ['Region'].transform(lambda grp : fillna_Region(grp)))
df_stack["Animal"] =
df_stack["Animal"].fillna(df_stack.groupby(['Country','Flower']) ['Animal'].transform(lambda grp : fillna_Region(grp)))
df_stack = df_stack.ffill(axis = 0)
df_stack = df_stack.bfill(axis =0)
print("-------After imputation------")
print(df_stack)
I have a dataframe like this one,
Continent % Renewable
Country
China Asia 2
United States North America 1
Japan Asia 1
United Kingdom Europe 1
Russian Federation Europe 2
Canada North America 5
Germany Europe 2
India Asia 1
France Europe 2
South Korea Asia 1
Italy Europe 3
Spain Europe 3
Iran Asia 1
Australia Australia 1
Brazil South America 5
where the % Renewableis a column created using the cut function,
Top15['% Renewable'] = pd.cut(Top15['% Renewable'], 5, labels=range(1,6))
when I group by Continentand % Renewable to count the number of countries in each subset I do,
count_groups = Top15.groupby(['Continent', '% Renewable']).size()
which is,
Continent % Renewable
Asia 1 4
2 1
Australia 1 1
Europe 1 1
2 3
3 2
North America 1 1
5 1
South America 5 1
The weird thing is the indexing now, if I index for a value that the category value is > 0 this gives me the value,
count_groups.loc['Asia', 1]
>> 4
if not,
count_groups.loc['Asia', 3]
>> IndexingError: Too many indexers
shouldn't it give me a 0 as there are no entries in that category? I would assume so as that dataframe was created using the groupby.
If not, can anyone suggest a procedure so I can preserve the 0 nr of countries for a category of % Renewable?
You have a Series with MultiIndex. Normally, we use tuples for indexing with MultiIndexes but pandas can be flexible about that.
In my opinion, count_groups.loc[('Asia', 3)] should raise a KeyError since this pair does not appear in the index but that's for pandas developers to decide I guess.
To return a default value from a Series, we can use get like we do in dictionaries:
count_groups.get(('Asia', 3), 0)
This will return 0 if the key does not exist.