Count the frequency of a recurring list — inside a list of lists

Question

I have a list of lists in python and I need to find how many times each sub-list has occurred. Here is a sample,

from collections import Counter
list1 = [[ 1         


        

Answer 1

Just convert the lists to tuple:

>>> c = Counter(tuple(x) for x in iter(list1))
>>> c
Counter({(1.0, 2.66666667, 1.33333333): 3, (1.0, 4.0, 2.5): 2, (1.0, 2.0, 2.0): 1})

Remember to do the same for lookup:

>>> c[tuple(list1[0])]
2