直方图：“TypeError，列表索引必须是整数，而不是str”

Question

I am trying to make a function that will take a character and a histogram and add an instance of that character to the histogram. My code so far is like this:

def add_to_hist(character, histogram):
    """Takes a character and a histogram and adds an occurrence
       of that character to the histogram.

    string, list -> list"""
    for c in character:
        if c not in histogram:
            histogram[c] = 1
        else:
            histogram[c] = histogram[c]+1
    return histogram

Every time I try to run the code it returns with TypeError: list indices must be integers, not str . Can anyone help me figure this out? My code actually might be entirely wrong, I'm very new at this. Thanks in advance!

Answer 1

That error is because you are trying to assign a key to a list , and list only can be indexed by intenger list[0] , list[1] , so on. So, hinstogram must be a dict not a list

Make sure when you call add_to_hist method, pass a dict. You can init a dict in that way:

histogram = {}

UPDATED

Based on your comment, you can't pass [['B',1],['a',3],['n',2],['!',1]] as param to add_to_his , because that is not a dict. It should be {'B':1,'a':3,'n':2,'!':1}