how to value counts of two columns in pandas

df = pd.DataFrame({'a':list('abssbab')})
df.groupby('a').count()

In [212]:
df = pd.DataFrame(np.random.randint(0, 2, (10, 4)), columns=list('abcd'))
df.apply(pd.Series.value_counts)
Out[212]:
   a  b  c  d
0  4  6  4  3
1  6  4  6  7

# importing pandas as pd 
import pandas as pd 
  
# sample dataframe 
df = pd.DataFrame({ 'A': ['foo', 'bar', 'g2g', 'g2g', 'g2g', 
                                'bar', 'bar', 'foo', 'bar'], 
                   'B': ['a', 'b', 'a', 'b', 'b', 'b', 'a', 'a', 'b'] }) 
  
# Multi-column frequency count 
count = df.groupby(['A']).count() 
print(count) 

# importing pandas as pd 
import pandas as pd 
  
# sample dataframe 
df = pd.DataFrame({'A': ['foo', 'bar', 'g2g', 'g2g', 'g2g', 
                         'bar', 'bar', 'foo', 'bar'], 
                  'B': ['a', 'b', 'a', 'b', 'b', 'b', 'a', 'a', 'b'] }) 
  
# frequency count of column A 
count = df['A'].value_counts() 
print(count)