CODEWITHSUNDEEP
pythonlist
Marko
Marko

Reputation: 67

How to find several most frequent elements in a list

My program below does find the most frequent element in a list:

numbers = [7, 1, 7, 9, 2, 9, 7, 3, 0]
counter = []

for num in range(10):
    n = numbers.count(num)
    counter.append(n)

largest = max(counter)
print(counter.index(largest))

Output is 7 which is correct.

However, if I add another 9 to the list:

numbers = [7, 1, 7, 9, 2, 9, 7, 3, 0, 9]

which means there are two most frequent elements in a list (in this case, both 7 and 9 are found three times there, as shown above), it only prints one of them - 7 in this case.

Is there any way how to change my code, so that the output will be correct?

Upvotes: 3

Views: 3293

Answers (6)

Thato Maphalla
Thato Maphalla

Reputation: 1

numbers = [1,4,4,4,8,8,9,0,4]
most_friquent = max(numbers,key=numbers.count)
print (most_friquent)

Upvotes: 0

Thierry Lathuille
Thierry Lathuille

Reputation: 24232

Here is a solution that works for any kind of data, not only for positive integers in a range known beforehand.

We count using a collections.Counter, extract the maximum count which is the count of the most_common number, then make a list of the numbers who have the same count:

from collections import Counter

numbers = [7, 1, 7, 9, 2, 9, 7, 3, 0, 9]
counts = Counter(numbers)
max_count = counts.most_common(1)[0][1]
out = [value for value, count in counts.most_common() if count == max_count]
print(out)
# [7, 9]

Upvotes: 6

Gius
Gius

Reputation: 514

Here's my way:

numbers = [7, 1, 7, 9, 2, 9, 7, 3, 0, 9]
counter = set([x for x in numbers if numbers.count(x) > 1])
print(max(counter))
# 9

Upvotes: 0

Haiz
Haiz

Reputation: 134

for num in range(10):
    if counter[num] == largest:
        print(num)

Upvotes: 1

sammy
sammy

Reputation: 867

As the indices of the list counter reflect a sorted value list, a simple solution would be to take the highest index: len(counter) - 1 - counter[::-1].index(largest)

Upvotes: 0

Tal Avissar
Tal Avissar

Reputation: 10304

from itertools import groupby

numbers = [7, 1, 7, 9, 2, 9, 7, 3, 0, 9]

counts = [(i, len(list(c))) for i,c in groupby(numbers)]    
print(counts)

Upvotes: 0

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