如何将 csv 读取为具有多个值的字典?

How to read csv to dictionary with multiple values?

我想把下面的数据读成这样:

{
  'a' : ['row1,'row2','row3'], 
  'b' : ['row1,'row2','row3']
}
columns A columns B
a row1
a row2
a row3
b row 1
b row 2
b row 3
with open(FILE) as file:
    contents = [row for row in csv.DictReader(file, delimiter=';')]
data = {
    'a': [row['columns B'] for row in contents if row['columns A'] == 'a'],
    'b': [row['columns B'] for row in contents if row['columns A'] == 'b']}

data
# >> {'a': ['row1', 'row2', 'row3'], 'b': ['row 1', 'row 2', 'row 3']}

已通过 Python3 测试,但也应该可以与 Python2 一起使用。如果没有,请告诉我。