Count elements in a list python

Question

I need to be able to count how many of the string \"O\" is in my list

top_board = [
    [None, None, None, None, None, None, None, None, None],
    [None, None,         


        

Answer 1

Try this:

sum(x.count("O") for x in top_board)

Answer 2

if [j for i in top_board for j in i].count('O'):
    print "O is present in the list"

Answer 3

cnt = sum([lst.count('O') for lst in top_board])
# then do something depending on cnt

Answer 4

def count_O(l):
    count = 0
    for sublist in l:
        count += sublist.count("O")
    return count


if count_O(top_board) == 0:
    #do something

Answer 5

Update

sum([sum([1 for x in y if x == "O"]) for y in top_board])

(hadn't notice the nesting...)

Answer 6

Since you asked for a function:

def count_O (top_board):
    if True in ["O" in e for e in top_board]:
        print "O found"