This is obviously simple, but as a numpy newbe I'm getting stuck.
I have a CSV file that contains 3 columns, the State, the Office ID, and the Sales for that office.
I want to calculate the percentage of sales per office in a given state (total of all percentages in each state is 100%).
df = pd.DataFrame({'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': range(1, 7) * 2,
'sales': [np.random.randint(100000, 999999)
for _ in range(12)]})
df.groupby(['state', 'office_id']).agg({'sales': 'sum'})
This returns:
sales
state office_id
AZ 2 839507
4 373917
6 347225
CA 1 798585
3 890850
5 454423
CO 1 819975
3 202969
5 614011
WA 2 163942
4 369858
6 959285
I can't seem to figure out how to "reach up" to the state level of the groupby to total up the sales for the entire state to calculate the fraction.
I think this would do the trick in 1 line:
df.groupby(['state', 'office_id']).sum().transform(lambda x: x/np.sum(x)*100)
I think this needs benchmarking. Using OP's original DataFrame,
df = pd.DataFrame({
'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': range(1, 7) * 2,
'sales': [np.random.randint(100000, 999999) for _ in range(12)]
})
As commented on his answer, Andy takes full advantage of vectorisation and pandas indexing.
c = df.groupby(['state', 'office_id'])['sales'].sum().rename("count")
c / c.groupby(level=0).sum()
3.42 ms ± 16.7 µs per loop
(mean ± std. dev. of 7 runs, 100 loops each)
state_office = df.groupby(['state', 'office_id']).agg({'sales': 'sum'})
state = df.groupby(['state']).agg({'sales': 'sum'})
state_office.div(state, level='state') * 100
4.66 ms ± 24.4 µs per loop
(mean ± std. dev. of 7 runs, 100 loops each)
This is the slowest answer as it calculates x.sum() for each x in level 0.
For me, this is still a useful answer, though not in its current form. For quick EDA on smaller datasets, apply allows you use method chaining to write this in a single line. We therefore remove the need decide on a variable's name, which is actually very computationally expensive for your most valuable resource (your brain!!).
Here is the modification,
(
df.groupby(['state', 'office_id'])
.agg({'sales': 'sum'})
.groupby(level=0)
.apply(lambda x: 100 * x / float(x.sum()))
)
10.6 ms ± 81.5 µs per loop
(mean ± std. dev. of 7 runs, 100 loops each)
So no one is going care about 6ms on a small dataset. However, this is 3x speed up and, on a larger dataset with high cardinality groupbys this is going to make a massive difference.
Adding to the above code, we make a DataFrame with shape (12,000,000, 3) with 14412 state categories and 600 office_ids,
import string
import numpy as np
import pandas as pd
np.random.seed(0)
groups = [
''.join(i) for i in zip(
np.random.choice(np.array([i for i in string.ascii_lowercase]), 30000),
np.random.choice(np.array([i for i in string.ascii_lowercase]), 30000),
np.random.choice(np.array([i for i in string.ascii_lowercase]), 30000),
)
]
df = pd.DataFrame({'state': groups * 400,
'office_id': list(range(1, 601)) * 20000,
'sales': [np.random.randint(100000, 999999)
for _ in range(12)] * 1000000
})
Using Andy's,
2 s ± 10.4 ms per loop
(mean ± std. dev. of 7 runs, 1 loop each)
and exp1orer
19 s ± 77.1 ms per loop
(mean ± std. dev. of 7 runs, 1 loop each)
So now we see x10 speed up on large, high cardinality datasets.
Be sure to UV these three answers if you UV this one!!
You can sum the whole DataFrame and divide by the state total:
# Copying setup from Paul H answer
import numpy as np
import pandas as pd
np.random.seed(0)
df = pd.DataFrame({'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': list(range(1, 7)) * 2,
'sales': [np.random.randint(100000, 999999) for _ in range(12)]})
# Add a column with the sales divided by state total sales.
df['sales_ratio'] = (df / df.groupby(['state']).transform(sum))['sales']
df
Returns
office_id sales state sales_ratio
0 1 405711 CA 0.193319
1 2 535829 WA 0.347072
2 3 217952 CO 0.198743
3 4 252315 AZ 0.192500
4 5 982371 CA 0.468094
5 6 459783 WA 0.297815
6 1 404137 CO 0.368519
7 2 222579 AZ 0.169814
8 3 710581 CA 0.338587
9 4 548242 WA 0.355113
10 5 474564 CO 0.432739
11 6 835831 AZ 0.637686
But note that this only works because all columns other than state are numeric, enabling summation of the entire DataFrame. For example, if office_id is character instead, you get an error:
df.office_id = df.office_id.astype(str)
df['sales_ratio'] = (df / df.groupby(['state']).transform(sum))['sales']
TypeError: unsupported operand type(s) for /: 'str' and 'str'
As someone who is also learning pandas I found the other answers a bit implicit as pandas hides most of the work behind the scenes. Namely in how the operation works by automatically matching up column and index names. This code should be equivalent to a step by step version of @exp1orer's accepted answer
With the df, I'll call it by the alias state_office_sales:
sales
state office_id
AZ 2 839507
4 373917
6 347225
CA 1 798585
3 890850
5 454423
CO 1 819975
3 202969
5 614011
WA 2 163942
4 369858
6 959285
state_total_sales is state_office_sales grouped by total sums in index level 0 (leftmost).
In: state_total_sales = df.groupby(level=0).sum()
state_total_sales
Out:
sales
state
AZ 2448009
CA 2832270
CO 1495486
WA 595859
Because the two dataframes share an index-name and a column-name pandas will find the appropriate locations through shared indexes like:
In: state_office_sales / state_total_sales
Out:
sales
state office_id
AZ 2 0.448640
4 0.125865
6 0.425496
CA 1 0.288022
3 0.322169
5 0.389809
CO 1 0.206684
3 0.357891
5 0.435425
WA 2 0.321689
4 0.346325
6 0.331986
To illustrate this even better, here is a partial total with a XX that has no equivalent. Pandas will match the location based on index and column names, where there is no overlap pandas will ignore it:
In: partial_total = pd.DataFrame(
data = {'sales' : [2448009, 595859, 99999]},
index = ['AZ', 'WA', 'XX' ]
)
partial_total.index.name = 'state'
Out:
sales
state
AZ 2448009
WA 595859
XX 99999
In: state_office_sales / partial_total
Out:
sales
state office_id
AZ 2 0.448640
4 0.125865
6 0.425496
CA 1 NaN
3 NaN
5 NaN
CO 1 NaN
3 NaN
5 NaN
WA 2 0.321689
4 0.346325
6 0.331986
This becomes very clear when there are no shared indexes or columns. Here missing_index_totals is equal to state_total_sales except that it has a no index-name.
In: missing_index_totals = state_total_sales.rename_axis("")
missing_index_totals
Out:
sales
AZ 2448009
CA 2832270
CO 1495486
WA 595859
In: state_office_sales / missing_index_totals
Out: ValueError: cannot join with no overlapping index names
I realize there are already good answers here.
I nevertheless would like to contribute my own, because I feel for an elementary, simple question like this, there should be a short solution that is understandable at a glance.
It should also work in a way that I can add the percentages as a new column, leaving the rest of the dataframe untouched. Last but not least, it should generalize in an obvious way to the case in which there is more than one grouping level (e.g., state and country instead of only state).
The following snippet fulfills these criteria:
df['sales_ratio'] = df.groupby(['state'])['sales'].transform(lambda x: x/x.sum())
Note that if you're still using Python 2, you'll have to replace the x in the denominator of the lambda term by float(x).
Simple way I have used is a merge after the 2 groupby's then doing simple division.
import numpy as np
import pandas as pd
np.random.seed(0)
df = pd.DataFrame({'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': list(range(1, 7)) * 2,
'sales': [np.random.randint(100000, 999999) for _ in range(12)]})
state_office = df.groupby(['state', 'office_id'])['sales'].sum().reset_index()
state = df.groupby(['state'])['sales'].sum().reset_index()
state_office = state_office.merge(state, left_on='state', right_on ='state', how = 'left')
state_office['sales_ratio'] = 100*(state_office['sales_x']/state_office['sales_y'])
state office_id sales_x sales_y sales_ratio
0 AZ 2 222579 1310725 16.981365
1 AZ 4 252315 1310725 19.250033
2 AZ 6 835831 1310725 63.768601
3 CA 1 405711 2098663 19.331879
4 CA 3 710581 2098663 33.858747
5 CA 5 982371 2098663 46.809373
6 CO 1 404137 1096653 36.851857
7 CO 3 217952 1096653 19.874290
8 CO 5 474564 1096653 43.273852
9 WA 2 535829 1543854 34.707233
10 WA 4 548242 1543854 35.511259
11 WA 6 459783 1543854 29.781508
df = pd.DataFrame({'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': list(range(1, 7)) * 2,
'sales': [np.random.randint(100000, 999999)
for _ in range(12)]})
grouped = df.groupby(['state', 'office_id'])
100*grouped.sum()/df[["state","sales"]].groupby('state').sum()
Returns:
sales
state office_id
AZ 2 54.587910
4 33.009225
6 12.402865
CA 1 32.046582
3 44.937684
5 23.015735
CO 1 21.099989
3 31.848658
5 47.051353
WA 2 43.882790
4 10.265275
6 45.851935
(This solution is inspired from this article https://pbpython.com/pandas_transform.html)
I find the following solution to be the simplest(and probably the fastest) using transformation:
Transformation: While aggregation must return a reduced version of the data, transformation can return some transformed version of the full data to recombine. For such a transformation, the output is the same shape as the input.
So using transformation, the solution is 1-liner:
df['%'] = 100 * df['sales'] / df.groupby('state')['sales'].transform('sum')
And if you print:
print(df.sort_values(['state', 'office_id']).reset_index(drop=True))
state office_id sales %
0 AZ 2 195197 9.844309
1 AZ 4 877890 44.274352
2 AZ 6 909754 45.881339
3 CA 1 614752 50.415708
4 CA 3 395340 32.421767
5 CA 5 209274 17.162525
6 CO 1 549430 42.659629
7 CO 3 457514 35.522956
8 CO 5 280995 21.817415
9 WA 2 828238 35.696929
10 WA 4 719366 31.004563
11 WA 6 772590 33.298509
For conciseness I'd use the SeriesGroupBy:
In [11]: c = df.groupby(['state', 'office_id'])['sales'].sum().rename("count")
In [12]: c
Out[12]:
state office_id
AZ 2 925105
4 592852
6 362198
CA 1 819164
3 743055
5 292885
CO 1 525994
3 338378
5 490335
WA 2 623380
4 441560
6 451428
Name: count, dtype: int64
In [13]: c / c.groupby(level=0).sum()
Out[13]:
state office_id
AZ 2 0.492037
4 0.315321
6 0.192643
CA 1 0.441573
3 0.400546
5 0.157881
CO 1 0.388271
3 0.249779
5 0.361949
WA 2 0.411101
4 0.291196
6 0.297703
Name: count, dtype: float64
For multiple groups you have to use transform (using Radical's df):
In [21]: c = df.groupby(["Group 1","Group 2","Final Group"])["Numbers I want as percents"].sum().rename("count")
In [22]: c / c.groupby(level=[0, 1]).transform("sum")
Out[22]:
Group 1 Group 2 Final Group
AAHQ BOSC OWON 0.331006
TLAM 0.668994
MQVF BWSI 0.288961
FXZM 0.711039
ODWV NFCH 0.262395
...
Name: count, dtype: float64
This seems to be slightly more performant than the other answers (just less than twice the speed of Radical's answer, for me ~0.08s).
You need to make a second groupby object that groups by the states, and then use the div method:
import numpy as np
import pandas as pd
np.random.seed(0)
df = pd.DataFrame({'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': list(range(1, 7)) * 2,
'sales': [np.random.randint(100000, 999999) for _ in range(12)]})
state_office = df.groupby(['state', 'office_id']).agg({'sales': 'sum'})
state = df.groupby(['state']).agg({'sales': 'sum'})
state_office.div(state, level='state') * 100
sales
state office_id
AZ 2 16.981365
4 19.250033
6 63.768601
CA 1 19.331879
3 33.858747
5 46.809373
CO 1 36.851857
3 19.874290
5 43.273852
WA 2 34.707233
4 35.511259
6 29.781508
the level='state' kwarg in div tells pandas to broadcast/join the dataframes base on the values in the state level of the index.
The most elegant way to find percentages across columns or index is to use pd.crosstab.
Sample Data
df = pd.DataFrame({'state': ['CA', 'WA', 'CO', 'AZ'] * 3,
'office_id': list(range(1, 7)) * 2,
'sales': [np.random.randint(100000, 999999) for _ in range(12)]})
The output dataframe is like this
print(df)
state office_id sales
0 CA 1 764505
1 WA 2 313980
2 CO 3 558645
3 AZ 4 883433
4 CA 5 301244
5 WA 6 752009
6 CO 1 457208
7 AZ 2 259657
8 CA 3 584471
9 WA 4 122358
10 CO 5 721845
11 AZ 6 136928
Just specify the index, columns and the values to aggregate. The normalize keyword will calculate % across index or columns depending upon the context.
result = pd.crosstab(index=df['state'],
columns=df['office_id'],
values=df['sales'],
aggfunc='sum',
normalize='index').applymap('{:.2f}%'.format)
print(result)
office_id 1 2 3 4 5 6
state
AZ 0.00% 0.20% 0.00% 0.69% 0.00% 0.11%
CA 0.46% 0.00% 0.35% 0.00% 0.18% 0.00%
CO 0.26% 0.00% 0.32% 0.00% 0.42% 0.00%
WA 0.00% 0.26% 0.00% 0.10% 0.00% 0.63%
I know that this is an old question, but exp1orer's answer is very slow for datasets with a large number unique groups (probably because of the lambda). I built off of their answer to turn it into an array calculation so now it's super fast! Below is the example code:
Create the test dataframe with 50,000 unique groups
import random
import string
import pandas as pd
import numpy as np
np.random.seed(0)
# This is the total number of groups to be created
NumberOfGroups = 50000
# Create a lot of groups (random strings of 4 letters)
Group1 = [''.join(random.choice(string.ascii_uppercase) for _ in range(4)) for x in range(NumberOfGroups/10)]*10
Group2 = [''.join(random.choice(string.ascii_uppercase) for _ in range(4)) for x in range(NumberOfGroups/2)]*2
FinalGroup = [''.join(random.choice(string.ascii_uppercase) for _ in range(4)) for x in range(NumberOfGroups)]
# Make the numbers
NumbersForPercents = [np.random.randint(100, 999) for _ in range(NumberOfGroups)]
# Make the dataframe
df = pd.DataFrame({'Group 1': Group1,
'Group 2': Group2,
'Final Group': FinalGroup,
'Numbers I want as percents': NumbersForPercents})
When grouped it looks like:
Numbers I want as percents
Group 1 Group 2 Final Group
AAAH AQYR RMCH 847
XDCL 182
DQGO ALVF 132
AVPH 894
OVGH NVOO 650
VKQP 857
VNLY HYFW 884
MOYH 469
XOOC GIDS 168
HTOY 544
AACE HNXU RAXK 243
YZNK 750
NOYI NYGC 399
ZYCI 614
QKGK CRLF 520
UXNA 970
TXAR MLNB 356
NMFJ 904
VQYG NPON 504
QPKQ 948
...
[50000 rows x 1 columns]
Array method of finding percentage:
# Initial grouping (basically a sorted version of df)
PreGroupby_df = df.groupby(["Group 1","Group 2","Final Group"]).agg({'Numbers I want as percents': 'sum'}).reset_index()
# Get the sum of values for the "final group", append "_Sum" to it's column name, and change it into a dataframe (.reset_index)
SumGroup_df = df.groupby(["Group 1","Group 2"]).agg({'Numbers I want as percents': 'sum'}).add_suffix('_Sum').reset_index()
# Merge the two dataframes
Percents_df = pd.merge(PreGroupby_df, SumGroup_df)
# Divide the two columns
Percents_df["Percent of Final Group"] = Percents_df["Numbers I want as percents"] / Percents_df["Numbers I want as percents_Sum"] * 100
# Drop the extra _Sum column
Percents_df.drop(["Numbers I want as percents_Sum"], inplace=True, axis=1)
This method takes about ~0.15 seconds
Top answer method (using lambda function):
state_office = df.groupby(['Group 1','Group 2','Final Group']).agg({'Numbers I want as percents': 'sum'})
state_pcts = state_office.groupby(level=['Group 1','Group 2']).apply(lambda x: 100 * x / float(x.sum()))
This method takes about ~21 seconds to produce the same result.
The result:
Group 1 Group 2 Final Group Numbers I want as percents Percent of Final Group
0 AAAH AQYR RMCH 847 82.312925
1 AAAH AQYR XDCL 182 17.687075
2 AAAH DQGO ALVF 132 12.865497
3 AAAH DQGO AVPH 894 87.134503
4 AAAH OVGH NVOO 650 43.132050
5 AAAH OVGH VKQP 857 56.867950
6 AAAH VNLY HYFW 884 65.336290
7 AAAH VNLY MOYH 469 34.663710
8 AAAH XOOC GIDS 168 23.595506
9 AAAH XOOC HTOY 544 76.404494
One-line solution:
df.join(
df.groupby('state').agg(state_total=('sales', 'sum')),
on='state'
).eval('sales / state_total')
This returns a Series of per-office ratios -- can be used on it's own or assigned to the original Dataframe.
Source: Stackoverflow.com