Here are the things you need to do to count the number of elements that are less than 'N' in each column.
- Get the list of columns.
- Use those columns on the dataframe to check the values in those columns.
- Then apply the count() function to count the number.
Check the following example:
>>> import numpy as np
>>> import pandas as pd
>>> df = pd.DataFrame({'a':np.random.permutation(20), 'b':np.random.permutation(20), 'c':np.random.permutation(20)})
>>> df
a b c
0 16 3 0
1 5 15 11
2 1 13 19
3 2 1 3
4 13 7 4
5 14 17 5
6 10 8 12
7 0 4 8
8 3 9 7
9 4 16 15
10 6 0 10
11 15 2 1
12 12 10 2
13 18 14 9
14 8 12 6
15 9 5 13
16 19 19 14
17 7 18 18
18 17 6 16
19 11 11 17
>>> df[df[df.columns] <10]
a b c
0 NaN 3.0 0.0
1 5.0 NaN NaN
2 1.0 NaN NaN
3 2.0 1.0 3.0
4 NaN 7.0 4.0
5 NaN NaN 5.0
6 NaN 8.0 NaN
7 0.0 4.0 8.0
8 3.0 9.0 7.0
9 4.0 NaN NaN
10 6.0 0.0 NaN
11 NaN 2.0 1.0
12 NaN NaN 2.0
13 NaN NaN 9.0
14 8.0 NaN 6.0
15 9.0 5.0 NaN
16 NaN NaN NaN
17 7.0 NaN NaN
18 NaN 6.0 NaN
19 NaN NaN NaN
>>> df[df[df.columns] <10].count()
a 10
b 10
c 10
Here all the columns have ten elements that are less than 10.