列表中的python计数重复

Question

我有这个清单：

['Boston Americans', 'New York Giants', 'Chicago White Sox', 'Chicago Cubs', 'Chicago Cubs', 'Pittsburgh Pirates', 'Philadelphia Athletics', 'Philadelphia Athletics', 'Boston Red Sox', 'Philadelphia Athletics', 'Boston Braves', 'Boston Red Sox', 'Boston Red Sox', 'Chicago White Sox', 'Boston Red Sox', 'Cincinnati Reds', 'Cleveland Indians', 'New York Giants', 'New York Giants', 'New York Yankees', 'Washington Senators', 'Pittsburgh Pirates', 'St. Louis Cardinals', 'New York Yankees', 'New York Yankees', 'Philadelphia Athletics', 'Philadelphia Athletics', 'St. Louis Cardinals', 'New York Yankees', 'New York Giants', 'St. Louis Cardinals', 'Detroit Tigers', 'New York Yankees', 'New York Yankees', 'New York Yankees', 'New York Yankees', 'Cincinnati Reds', 'New York Yankees', 'St. Louis Cardinals', 'New York Yankees', 'St. Louis Cardinals', 'Detroit Tigers', 'St. Louis Cardinals', 'New York Yankees', 'Cleveland Indians', 'New York Yankees', 'New York Yankees']

如何在不使用计数、追加或设置方法或导入的情况下从此列表中删除重复项？

或者我真正想要的是：我怎样才能把那个列表打印出来：

Boston Americans 5
New York Giants 2
team_name  number_of_duplicates
team_name  number_of_duplicates
team_name  number_of_duplicates

Answer 1

要计算列表中每个条目的数量，您可以使用模块中的Counter类collections：

l =['Boston Americans', 'New York Giants', 'Chicago White Sox', 'Chicago Cubs', 'Chicago Cubs', 'Pittsburgh Pirates', 'Philadelphia Athletics', 'Philadelphia Athletics', 'Boston Red Sox', 'Philadelphia Athletics', 'Boston Braves', 'Boston Red Sox', 'Boston Red Sox', 'Chicago White Sox', 'Boston Red Sox', 'Cincinnati Reds', 'Cleveland Indians', 'New York Giants', 'New York Giants', 'New York Yankees', 'Washington Senators', 'Pittsburgh Pirates', 'St. Louis Cardinals', 'New York Yankees', 'New York Yankees', 'Philadelphia Athletics', 'Philadelphia Athletics', 'St. Louis Cardinals', 'New York Yankees', 'New York Giants', 'St. Louis Cardinals', 'Detroit Tigers', 'New York Yankees', 'New York Yankees', 'New York Yankees', 'New York Yankees', 'Cincinnati Reds', 'New York Yankees', 'St. Louis Cardinals', 'New York Yankees', 'St. Louis Cardinals', 'Detroit Tigers', 'St. Louis Cardinals', 'New York Yankees', 'Cleveland Indians', 'New York Yankees', 'New York Yankees']

from collections import Counter
c = Counter(l) 
print(c)

c然后是一个Counter对象，它保存列表中每个不同条目/键的出现次数。由于Counter源自dict，您可以像访问任何其他字典一样访问它。

Counter({'New York Yankees': 13, 'St. Louis Cardinals': 6, 'Philadelphia Athletics': 5, 'New York Giants': 4, 'Boston Red Sox': 4, 'Chicago White Sox': 2, 'Pittsburgh Pirates': 2, 'Detroit Tigers': 2, 'Cincinnati Reds': 2, 'Cleveland Indians': 2, 'Chicago Cubs': 2, 'Boston Americans': 1, 'Boston Braves': 1, 'Washington Senators': 1})

Answer 2

l =['Boston Americans', 'New York Giants', 'Chicago White Sox', 'Chicago Cubs', 'Chicago Cubs', 'Pittsburgh Pirates', 'Philadelphia Athletics', 'Philadelphia Athletics', 'Boston Red Sox', 'Philadelphia Athletics', 'Boston Braves', 'Boston Red Sox', 'Boston Red Sox', 'Chicago White Sox', 'Boston Red Sox', 'Cincinnati Reds', 'Cleveland Indians', 'New York Giants', 'New York Giants', 'New York Yankees', 'Washington Senators', 'Pittsburgh Pirates', 'St. Louis Cardinals', 'New York Yankees', 'New York Yankees', 'Philadelphia Athletics', 'Philadelphia Athletics', 'St. Louis Cardinals', 'New York Yankees', 'New York Giants', 'St. Louis Cardinals', 'Detroit Tigers', 'New York Yankees', 'New York Yankees', 'New York Yankees', 'New York Yankees', 'Cincinnati Reds', 'New York Yankees', 'St. Louis Cardinals', 'New York Yankees', 'St. Louis Cardinals', 'Detroit Tigers', 'St. Louis Cardinals', 'New York Yankees', 'Cleveland Indians', 'New York Yankees', 'New York Yankees']

for team in [ele for ind, ele in enumerate(l,1) if ele not in l[ind:]]:
    print("{} {}".format(team,l.count(team)))
Boston Americans 1
Chicago Cubs 2
Boston Braves 1
Chicago White Sox 2
Boston Red Sox 4
Washington Senators 1
Pittsburgh Pirates 2
Philadelphia Athletics 5
New York Giants 4
Cincinnati Reds 2
Detroit Tigers 2
St. Louis Cardinals 6
Cleveland Indians 2
New York Yankees 13

list.count根本不使用：

for team in [ele for ind, ele in enumerate(l,1) if ele not in l[ind:]]:
    count = 0
    for ele in l:
        if team == ele:
            count += 1
    print("{} {}".format(team,count))
    count = 0

Boston Americans 1
Chicago Cubs 2
Boston Braves 1
Chicago White Sox 2
Boston Red Sox 4
Washington Senators 1
Pittsburgh Pirates 2
Philadelphia Athletics 5
New York Giants 4
Cincinnati Reds 2
Detroit Tigers 2
St. Louis Cardinals 6
Cleveland Indians 2
New York Yankees 13

您没有说是否可以使用字典：

d = {}

for team in l:
    # if we have not seen team before, create k/v pairing
    # setting value to 0, if team already in dict this does nothing
    d.setdefault(team,0)
    # increase the count for the team
    d[team] += 1
for team, count in d.items():
    print("{} {}".format(team,count))

Chicago White Sox 2
New York Giants 4
Cincinnati Reds 2
Boston Red Sox 4
New York Yankees 13
Philadelphia Athletics 5
Pittsburgh Pirates 2
St. Louis Cardinals 6
Washington Senators 1
Boston Braves 1
Boston Americans 1
Cleveland Indians 2
Detroit Tigers 2
Chicago Cubs 2