Question

I’m very new to Python and do know that my question is very simple but I’ve not found an existed question on SO yet.

I have an array contains string elements. Now I want to extract elements and count the number of appearances of them, them sort in descending order.

For example:

['ab' 'ab' 'ac']

then the output should be:

'ab' 2
'ac' 1

Also, it’s bad of me that I don’t know what is the best way to store my output (in a map, hash… or something like that? Again, I’m not sure)…

Thanks for any help.

Answer 1

This can be done using the Counter class from the collections module.

from collections import Counter
x = ['ab', 'ab', 'ac']
counts = Counter(x)

counts stores the count information for each element; the full list of methods can be found in the documentation, but probably all you care about is that you can access counts directly by treating counts like a hash:

counts['ab']
>>> 2