What is the opposite of any() function in python, e.g. without any

Question

Let's assume I have a df that looks like this:

import pandas as pd
d = {'group': ['A', 'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', 'B', 'C', 'C', 'C', 'C', 'C'], 
      'number': [0, 3, 2, 1, 2, 1, -2, 1, 2, 3, 4, 2, 1, -1, 0]}
df = pd.DataFrame(data=d)
df

    group   number
0   A       0
1   A       3
2   A       2
3   A       1
4   A       2
5   B       1
6   B      -2
7   B       1
8   B       2
9   B       3
10  C       4
11  C       2
12  C       1
13  C      -1
14  C       0

And I would like to delete a whole group if one of its values in the number column is negative. I can do:

df.groupby('group').filter(lambda g: (g.number < 0).any())

However this gives me the wrong output since this returns all groups with any rows that have a negative number in the number column. See below:

    group   number
5   B       1
6   B      -2
7   B       1
8   B       2
9   B       3
10  C       4
11  C       2
12  C       1
13  C      -1
14  C       0

How do I change this function to make it return all groups without any negative numbers in the number column. The output should be group A with its values.

Answer 1

Use the boolean NOT operator ~:

df.groupby('group').filter(lambda g: ~(g.number < 0).any())

Or check if all values don't match using De Morgan's Law:

df.groupby('group').filter(lambda g: (g.number >= 0).all())