df = data[[0]].join(data[1].str.get_dummies(', ').replace(0, ''))
print (df)
0 event2 event3 event4
0 userA 1 1
1 userB 1 1
2 userC 1
print (data[1].str.get_dummies(', '))
event2 event3 event4
0 1 1 0
1 0 1 1
2 1 0 0
602392714
清零编程群