pandas - number of unique rows occurrences in dataframe

Question

How can I count number of occurrences of each unique row in a DataFrame ?

data = {'x1': ['A','B','A','A','B','A','A','A'], 'x2': [1,3,2,2,3,1,2,3]}
df = pd.DataFrame(data)

df
  x1  x2
0  A   1
1  B   3
2  A   2
3  A   2
4  B   3
5  A   1
6  A   2
7  A   3

And I would like to obtain

   x1  x2 count 
0   A   1     2
1   A   2     3
2   A   3     1
3   B   3     2

Answer 1

IIUC you can pass param as_index=False as an arg to groupby :

In [100]:
df.groupby(['x1','x2'], as_index=False).count()

Out[100]:
  x1  x2  count
0  A   1      2
1  A   2      3
2  A   3      1
3  B   3      2

Answer 2

You could also drop duplicated rows:

In [4]: df.shape[0]
Out[4]: 8

In [5]: df.drop_duplicates().shape[0]
Out[5]: 4

Answer 3

There are two ways you can find unique occurence in your dataframe.

1st: Using drop_duplicates

df.drop_duplicates().sort_values('x1',ignore_index=True)

2nd: Using groupby.nunique

df.groupby(['x1','x2'], as_index=False).nunique()

For finding the number of occurrences, the answer from @EdChum will work precisely.