python .count for multidimensional arrays (list of lists)

>>> list = [['foobar', 'a', 'b'], ['x', 'c'], ['y', 'd', 'e', 'foobar'], ['z', 'f']]
>>> sum(x.count('foobar') for x in list)
2

>> from collections import Counter
>> counted = Counter([item for sublist in my_list for item in sublist])
>> counted.get('foobar', 'not found!')
>> 2
#or if not found in your counter
>> 'not found!'

This uses flattening of sublists and then using the collections module and Counter to produce the counts of words.

First join the lists together using itertools, then just count each occurrence using the Collections module:

import itertools
from collections import Counter

some_list = [['foobar', 'a', 'b'], ['x', 'c'], ['y', 'd', 'e', 'foobar'], ['z', 'f']]
totals = Counter(i for i in list(itertools.chain.from_iterable(some_list)))
print(totals["foobar"])