pandas Duplicated data Counting and getting unique elements
Example
Number of unique elements in a series:
In [1]: id_numbers = pd.Series([111, 112, 112, 114, 115, 118, 114, 118, 112])
In [2]: id_numbers.nunique()
Out[2]: 5
Get unique elements in a series:
In [3]: id_numbers.unique()
Out[3]: array([111, 112, 114, 115, 118], dtype=int64)
In [4]: df = pd.DataFrame({'Group': list('ABAABABAAB'),
'ID': [1, 1, 2, 3, 3, 2, 1, 2, 1, 3]})
In [5]: df
Out[5]:
Group ID
0 A 1
1 B 1
2 A 2
3 A 3
4 B 3
5 A 2
6 B 1
7 A 2
8 A 1
9 B 3
Number of unique elements in each group:
In [6]: df.groupby('Group')['ID'].nunique()
Out[6]:
Group
A 3
B 2
Name: ID, dtype: int64
Get of unique elements in each group:
In [7]: df.groupby('Group')['ID'].unique()
Out[7]:
Group
A [1, 2, 3]
B [1, 3]
Name: ID, dtype: object
