You an use merge
with parameter indicator
and outer join, query
for filtering and then remove helper column with drop
:
DataFrames are joined on all columns, so on
parameter can be omit.
print (pd.merge(a,b, indicator=True, how='outer')
.query('_merge=="left_only"')
.drop('_merge', axis=1))
0 1
0 1 10
2 3 30