Reputation: 1620
I need to count the instances of two columns in a dataframe by values. I get the same by using group & size, though I want to spit out 1. The flat value in each column combination 2. the name of the "last count" column (See also the what I want below).
df = pd.DataFrame([[1.1, 1.1, 1.1, 2.6, 2.5, 3.4,2.6,2.6,3.4,3.4,2.6,1.1,1.1,3.3], list('AAABBBBABCBDDD'), [1.1, 1.7, 2.5, 2.6, 3.3, 3.8,4.0,4.2,4.3,4.5,4.6,4.7,4.7,4.8], ['x/y/z','x/y','x/y/z/n','x/u','x','x/u/v','x/y/z','x','x/u/v/b','-','x/y','x/y/z','x','x/u/v/w'],['1','3','3','2','4','2','5','3','6','3','5','1','1','1']]).T
df.columns = ['col1','col2','col3','col4','col5']
df.groupby(['col5', 'col2']).size()
# this gives
col5 col2 <Note that this is unnamed>
1 A 1
D 3
2 B 2
3 A 3
C 1
4 B 1
5 B 2
6 B 1
dtype: int64
What I want -:
col5 col2 count_instances_of_this_combination
1 A 1
1 D 3
2 B 2
3 A 3
3 C 1
4 B 1
5 B 2
6 B 1
That is I explicitly want the 1st columns to print out the complete combination of col5, col2
Related question : Pandas DataFrame Groupby two columns and get counts
col1 col2 col3 col4 col5
0 1.1 A 1.1 x/y/z 1
1 1.1 A 1.7 x/y 3
2 1.1 A 2.5 x/y/z/n 3
3 2.6 B 2.6 x/u 2
4 2.5 B 3.3 x 4
5 3.4 B 3.8 x/u/v 2
6 2.6 B 4 x/y/z 5
7 2.6 A 4.2 x 3
8 3.4 B 4.3 x/u/v/b 6
9 3.4 C 4.5 - 3
10 2.6 B 4.6 x/y 5
11 1.1 D 4.7 x/y/z 1
12 1.1 D 4.7 x 1
13 3.3 D 4.8 x/u/v/w 1
This means the combination <1,A > occurred once, <2, B> occurred twice, <1,d> occurred thrice & so on.
Here's how it worked -:
Further to the answer below, on setting the sparity option to False, I did this to get the name .
pd.options.display.multi_sparse = False
# rest same a above..
s=pd.DataFrame({'s=pd.DataFrame({'count_instances_of_this_combination' : df.groupby(['query', 'product_id']).size()}).reset_index()' : df.groupby(['col5', 'col2']).size()}).reset_index()
This gives me a well formed data frame with the "3rd" column as a named column.
Upvotes: 2
Views: 2583
Reputation: 880299
Set the option:
pd.options.display.multi_sparse = False
Then:
import pandas as pd
pd.options.display.multi_sparse = False
df = pd.DataFrame(
[[1.1, 1.1, 1.1, 2.6, 2.5, 3.4,2.6,2.6,3.4,3.4,2.6,1.1,1.1,3.3],
list('AAABBBBABCBDDD'),
[1.1, 1.7, 2.5, 2.6, 3.3, 3.8,4.0,4.2,4.3,4.5,4.6,4.7,4.7,4.8],
['x/y/z','x/y','x/y/z/n','x/u','x','x/u/v','x/y/z','x','x/u/v/b','-','x/y',
'x/y/z','x','x/u/v/w'],
['1','3','3','2','4','2','5','3','6','3','5','1','1','1']]).T
df.columns = ['col1','col2','col3','col4','col5']
print(df.groupby(['col5', 'col2']).size())
yields
col5 col2
1 A 1
1 D 3
2 B 2
3 A 3
3 C 1
4 B 1
5 B 2
6 B 1
dtype: int64
Upvotes: 5