How do you “pivot” using conditions, aggregation, and concatenation in Pandas? - pandas

I have a dataframe in a format such as the following:
Index Name Fruit Quantity
0 John Apple Red 10
1 John Apple Green 5
2 John Orange Cali 12
3 Jane Apple Red 10
4 Jane Apple Green 5
5 Jane Orange Cali 18
6 Jane Orange Spain 2
I need to turn it into a dataframe such as this:
Index Name All Fruits Apples Total Oranges Total
0 John Apple Red, Apple Green, Orange Cali 15 12
1 Jane Apple Red, Apple Green, Orange Cali, Orange Spain 15 20
Question is how do I do this? I have looked at the groupby docs as well as a number of posts on pivot and aggregation but translating that into this use case somehow escapes me. Any help or pointers much appreciated.
Cheers!

Use GroupBy.agg with join, create column F by split and pass to DataFrame.pivot_table, last join together by DataFrame.join:
df1 = df.groupby('Name', sort=False)['Fruit'].agg(', '.join)
df2 = (df.assign(F = df['Fruit'].str.split().str[0])
.pivot_table(index='Name',
columns='F',
values='Quantity',
aggfunc='sum')
.add_suffix(' Total'))
df3 = df1.to_frame('All Fruits').join(df2).reset_index()
print (df3)
Name All Fruits Apple Total \
0 John Apple Red, Apple Green, Orange Cali 15
1 Jane Apple Red, Apple Green, Orange Cali, Orange Spain 15
Orange Total
0 12
1 20

Related

How do you groupby and aggregate using conditional statements in Pandas?

Expanding on the question here, I'm wondering how to add aggregation to the following based on conditions:
Index Name Item Quantity
0 John Apple Red 10
1 John Apple Green 5
2 John Orange Cali 12
3 Jane Apple Red 10
4 Jane Apple Green 5
5 Jane Orange Cali 18
6 Jane Orange Spain 2
7 John Banana 3
8 Jane Coconut 5
9 John Lime 10
... And so forth
What I need to do is getting this data converted into a dataframe like the following. Note: I am only interested in getting the total quantity of the apples and oranges both of them in separate columns, i.e. whatever other items appear in a certain group are not to be included in the aggregation done on column "Quantity" (but they are still to appear in the column "All items" as strings):
Index Name All Items Apples Total Oranges Total
0 John Apple Red, Apple Green, Orange Cali, Banana, Lime 15 12
1 Jane Apple Red, Apple Green, Orange Cali, Coconut 15 20
How would do I achieve that? Many thanks in advance!
You can use groupby and pivot_table after extracting Apple and Orange sub strings as below:
import re
s = df['Item'].str.extract("(Apple|Orange)",expand=False,flags=re.I)
# re.I used above is optional and is used for case insensitive matching
a = df.assign(Item_1=s).dropna(subset=['Item_1'])
out = (a.groupby("Name")['Item'].agg(",".join).to_frame().join(
a.pivot_table("Quantity","Name","Item_1",aggfunc=sum).add_suffix("_Total"))
.reset_index())
print(out)
Name Item Apple_Total \
0 Jane Apple Red,Apple Green,Orange Cali,Orange Spain 15
1 John Apple Red,Apple Green,Orange Cali 15
Orange_Total
0 20
1 12
EDIT:
For edited question, you can use the same code only except groupby on the original dataframe df instead of the subset a and then join:
out = (df.groupby("Name")['Item'].agg(",".join).to_frame().join(
a.pivot_table("Quantity","Name","Item_1",aggfunc=sum).add_suffix("_Total"))
.reset_index())
print(out)
Name Item Apple_Total \
0 Jane Apple Red,Apple Green,Orange Cali,Orange Spain... 15
1 John Apple Red,Apple Green,Orange Cali,Banana,Lime 15
Orange_Total
0 20
1 12
First Filter only the required rows using str.contains on the column Item
from io import StringIO
import pandas as pd
s = StringIO("""Name;Item;Quantity
John;Apple Red;10
John;Apple Green;5
John;Orange Cali;12
Jane;Apple Red;10
Jane;Apple Green;5
Jane;Orange Cali;18
Jane;Orange Spain;2
John;Banana;3
Jane;Coconut;5
John;Lime;10
""")
df = pd.read_csv(s,sep=';')
req_items_idx = df[df.Item.str.contains('Apple|Orange')].index
df_filtered = df.loc[req_items_idx,:]
Once you have them you can further pivot the data to get the required values based on Name
pivot_df = pd.pivot_table(df_filtered,index=['Name'],columns=['Item'],aggfunc='sum')
pivot_df.columns = pivot_df.columns.droplevel()
pivot_df.columns.name = None
pivot_df = pivot_df.reset_index()
Generate the Totals for Apples and Oranges
orange_columns = pivot_df.columns[pivot_df.columns.str.contains('Orange')].tolist()
apple_columns = pivot_df.columns[pivot_df.columns.str.contains('Apple')].tolist()
pivot_df['Apples Total'] = pivot_df.loc[:,apple_columns].sum(axis=1)
pivot_df['Orange Total'] = pivot_df.loc[:,orange_columns].sum(axis=1)
A wrapper function to combine the Items together
def combine_items(inp,columns):
res = []
for val,col in zip(inp.values,columns):
if not pd.isnull(val):
res += [col]
return ','.join(res)
req_columns = apple_columns+orange_columns
pivot_df['Items'] = pivot_df[apple_columns+orange_columns].apply(combine_items,args=([req_columns]),axis=1)
Finally you can get the required columns in a single place and print the values
total_columns = pivot_df.columns[pivot_df.columns.str.contains('Total')].tolist()
name_item_columns = pivot_df.columns[pivot_df.columns.str.contains('Name|Items')].tolist()
>>> pivot_df[name_item_columns+total_columns]
Name Items Apples Total Orange Total
0 Jane Apple Green,Apple Red,Orange Cali,Orange Spain 15.0 20.0
1 John Apple Green,Apple Red,Orange Cali 15.0 12.0
The answer is intended to outline the individual steps and approach one can take to solve something similar to this
Edits: fixed a bug.
To do this, before doing your groupby you can create your Total columns. These will contain a the number of apples and oranges in that row, depending whether that row's Item is apple or orange.
df['Apples Total'] = df.apply(lambda x: x.Quantity if ('Apple' in x.Item) else 0, axis=1)
df['Oranges Total'] = df.apply(lambda x: x.Quantity if ('Orange' in x.Item) else 0, axis=1)
When this is in place, groupby name and aggregate on each column. Sum on the total columns, and aggregate to list on the item column.
df.groupby('Name').agg({'Apples Total': 'sum',
'Oranges Total': 'sum',
'Item': lambda x: list(x)
})
df = pd.read_csv(StringIO("""
Index,Name,Item,Quantity
0,John,Apple Red,10
1,John,Apple Green,5
2,John,Orange Cali,12
3,Jane,Apple Red,10
4,Jane,Apple Green,5
5,Jane,Orange Cali,18
6,Jane,Orange Spain,2
7,John,Banana,3
8,Jane,Coconut,5
9,John,Lime,10
"""))
Getting list of items
grouping by name to get the list of items
items_list = pd.DataFrame(df.groupby(["Name"])["Item"].apply(list)).rename(columns={"Item": "All Items"})
items_list
All Items
Name
Jane [Apple Red, Apple Green, Orange Cali, Orange Spain, Coconut]
John [Apple Red, Apple Green, Orange Cali, Banana, Lime]
getting count of name item groups
renaming the temp df items column such that all the apples/oranges are treated similarly
temp2 = df.groupby(["Name", "Item"])['Quantity'].apply(sum)
temp2 = pd.DataFrame(temp2).reset_index().set_index("Name")
temp2['Item'] = temp2['Item'].str.replace(r'(?:.*)(apple|orange)(?:.*)', r'\1', case=False,regex=True)
temp2
Item Quantity
Name
Jane Apple 5
Jane Apple 10
Jane Coconut 5
Jane Orange 18
Jane Orange 2
John Apple 5
John Apple 10
John Banana 3
John Lime 10
John Orange 12
getting the required pivot table
pivot table for getting items count as separate column and retaining just apple orange count
pivot_df = pd.pivot_table(temp2, values='Quantity', columns='Item', index=["Name"], aggfunc=np.sum)
pivot_df = pivot_df[['Apple', 'Orange']]
pivot_df
Item Apple Orange
Name
Jane 15.0 20.0
John 15.0 12.0
merging the items list df and the pivot_df
output = items_list.merge(pivot_df, on="Name").rename(columns = {'Apple': 'Apples
Total', 'Orange': 'Oranges Total'})
output
All Items Apples Total Oranges Total
Name
Jane [Apple Red, Apple Green, Orange Cali, Orange Spain, Coconut] 15.0 20.0
John [Apple Red, Apple Green, Orange Cali, Banana, Lime] 15.0 12.0

Divide two dataframe by matching part of the strings in Index

Please help, why df3 is not working? got error "merging with more than one level overlap on a multi-index is not implemented"
raw data:
LastName FirstName Year Cat Pay
0 Johnson David 2020 Apple 100
1 Bird Demi 2020 Apple 60
2 Bird Demi 2019 Banana 100
3 Johnson David 2019 Banana 100
df1=df.groupby(['LastName', 'FirstName']) ['Pay'].agg(['min','max', 'mean', 'sum'])
df2 = df.groupby(['LastName','FirstName','Year'])['Pay'].mean()
df3=pd.DataFrame()
df3["PCT"] = df1['mean']/df2

Pandas filter maximum groupby

I have Pandas df:
family age fruits
------------------
Brown 12 7
Brown 33 5
Yellow 28 3
Yellow 11 9
I want to get ages with next conditions:
Group by family;
Having maximum of fruits
So result df will be:
family age
-----------
Brown 12
Yellow 11
We can do:
(df.sort_values(['family','fruits'], ascending=[True,False])
.drop_duplicates('family')
)
Output:
family age fruits
0 Brown 12 7
3 Yellow 11 9
Or with groupby().idxmax()
df.loc[df.groupby('family').fruits.idxmax(), ['family','age'] ]
Output:
family age
0 Brown 12
3 Yellow 11
Use head after sort_values
df.sort_values(
['family','fruits'], ascending=[True,False])
.groupby('family').head(1)

pandas search a value in a dataframe column

I have following dataframe and i want to search apple in column fruits and display all the rows if apple is found.
Before :
number fruits purchase
0 apple yes
mango
banana
1 apple no
cheery
2 mango yes
banana
3 apple yes
orange
4 grapes no
pear
After:
number fruits purchase
0 apple yes
mango
banana
1 apple no
cheery
3 apple yes
orange
Use groupby and filter to filter groups that contain 'apple':
df['number'] = df['number'].ffill()
df.groupby('number').filter(lambda x: (x['fruits'] == 'apple').any())
df_out.assign(number = df_out['number'].mask(df.number.duplicated()))\
.replace(np.nan,'')
Output:
number fruits purchase
0 0 apple yes
1 mango
2 banana
3 1 apple no
4 cheery
7 3 apple yes
8 orange
It looks like you're using 'number' as the index, so I'm going to assume that.
Get the numbers where 'apple' is present, and slice into those:
idx = df.index[df.fruits == 'apple']
df.loc[idx]

(pandas) Create new column based on first element in groupby object

Say I have the following dataframe:
>>> df = pd.DataFrame({'Person': ['bob', 'jim', 'joe', 'bob', 'jim', 'joe'], 'Color':['blue', 'green', 'orange', 'yellow', 'pink', 'purple']})
>>> df
Color Person
0 blue bob
1 green jim
2 orange joe
3 yellow bob
4 pink jim
5 purple joe
And I want to create a new column that represents the first color seen for each person:
Color Person First Color
0 blue bob blue
1 green jim green
2 orange joe orange
3 yellow bob blue
4 pink jim green
5 purple joe orange
I have come to a solution but it seems really inefficient:
>>> df['First Color'] = 0
>>> groups = df.groupby(['Person'])['Color']
>>> for g in groups:
... first_color = g[1].iloc[0]
... df['First Color'].loc[df['Person']==g[0]] = first_color
Is there a faster way to do this all at once where it doesn't have to iterate through the groupby object?
You need transform with first:
print (df.groupby('Person')['Color'].transform('first'))
0 blue
1 green
2 orange
3 blue
4 green
5 orange
Name: Color, dtype: object
df['First_Col'] = df.groupby('Person')['Color'].transform('first')
print (df)
Color Person First_Col
0 blue bob blue
1 green jim green
2 orange joe orange
3 yellow bob blue
4 pink jim green
5 purple joe orange
use transform() method:
In [177]: df['First_Col'] = df.groupby('Person')['Color'].transform('first')
In [178]: df
Out[178]:
Color Person First_Col
0 blue bob blue
1 green jim green
2 orange joe orange
3 yellow bob blue
4 pink jim green
5 purple joe orange