summing the dice trials and histogram plot

Question

I am stuck in a code in python which takes in number of dices and number of rolls and returns the sum of numbers obtained. It should also print the histogram of the sum. I am st

Answer 1

Your problem here is that you can't arbitrarily index into an empty list:

l = []
l[13] += 1 # fails with IndexError

Instead, you could use a defaultdict, which is a special type of dictionary that doesn't mind if a key hasn't been used yet:

from collections import defaultdict
d = defaultdict(int) # default to integer (0)
d[13] += 1 # works fine, adds 1 to the default

or Counter, which is designed for cases like this ("provided to support convenient and rapid tallies") and provides extra handy functions (like most_common(n), to get the n most common entries):

from collections import Counter
c = Counter()
c[13] += 1

To manually use a standard dict to do this, just add a check:

d = {}
if 13 in d: # already there
    d[13] += 1 # increment
else: # not already there
    d[13] = 1 # create