python count duplicate in list

Question

i have this list:

['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']

How can i remove duplicate from this list without using the count, append or the set method or imports?

Or what i really want is: how can i turn that list to print out like this:

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

Answer 1

To count how many of each entry there are in the list you can use the Counter class in the collections module:

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 is then a Counter object which holds the number of occurrences in the list for each distinct entry/key. As Counter is derived from dict, you can access it like any other dictionary.

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})