打开Excel把里面某一列所有相同的按顺序排列在下面行，不同的用空行隔开

data = []
with open('data.txt') as f:
    for line in f:
        data.append(line.strip())
# print(data)

# ['a', 'b', 'c', 'c', 'd', 'e', 'e', 'e', 'f', 'f', 'g']

last_value = ''
for i in range(len(data)):
    if data[i] == last_value:
        print(data[i], end = ' ')
    else:
        print('')
        print(data[i], end = ' ')
    last_value = data[i]