Find the Item With Maximum Occurrences in a List

Find the item with maximum occurrences in a list

Here is a defaultdict solution that will work with Python versions 2.5 and above:

from collections import defaultdict

L = [1,2,45,55,5,4,4,4,4,4,4,5456,56,6,7,67]
d = defaultdict(int)
for i in L:
    d[i] += 1
result = max(d.iteritems(), key=lambda x: x[1])
print result
# (4, 6)
# The number 4 occurs 6 times

Note if L = [1, 2, 45, 55, 5, 4, 4, 4, 4, 4, 4, 5456, 7, 7, 7, 7, 7, 56, 6, 7, 67]
then there are six 4s and six 7s. However, the result will be (4, 6) i.e. six 4s.

No. of occurrences of maximum item in a list

Use max and list.count:

max_element= max(L)
count= L.count(max_element)
print(count)

Python: Counting maximum occurences of an item in a list with ties allowed

Build a Counter from the list and take the items that match the highest count using a list comprehension:

from collections import Counter

lst = [1,1,2,2]

c = Counter(lst)
maximums = [x for x in c if c[x] == c.most_common(1)[0][1]]
print(maximums)
# [1, 2]

The Counter approach take counts in one pass (O(n)) whereas the list.count approach has O(n^2) time complexity as it passes through the list with each call.

Retrieve elements with max occurences with a DRAW(tie) in the max occurrence

You could do something like this:

counts = df[0].value_counts()
counts = counts[counts == counts.max()]

Output:

>>> counts
s    3
d    3
Name: 0, dtype: int64

>>> counts['s']
3

>>> counts['d']
3

Maximum Number of Occurrences of Any Item in Counter object / list

Since Pranav types faster than me, here is another potential answer to your problem:

ans = max(Counter(x for row in grid for x in row if x!=0).values())

I thought about irregular nested lists and this is what can do it:

unfurl=lambda x: sum(map(unfurl,x),[]) if isinstance(x,list) or isinstance(x, tuple) else [x]
ans = max(Counter(unfurl(grid)).values())

I am trying to find the maximum occurrences of a string in a list using Python [closed]

Instead of writing your own algorithm, you could simply use the builtin Counter from collections package. This class is basically a dictionary with items as keys and frequencies as values:

from collections import Counter
string = 'mary, bob, mary, bob, alex, julie'
names = [name.strip() for name in string.split(', ')]
frequencies = Counter(names)
max_frequency = max(frequencies.values())
max_frequency_names = [name 
                       for name, frequency in frequencies.items() 
                       if frequency == max_frequency]
print(max_frequency_names)

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