What is the preferred way to count number of ocurrances of certain character in string (Python)?

问题

How do I do this without str.count(), because it is listed as deprecated in Python v2.7.3 documentation?

I am unable to find what I should use instead.

回答1:

Use str.count() - it's not listed as deprecated.

(Python 2.7.3, Python 3.2.3 - both have no notes about being deprecated).

>>> "test".count("t")
2

I'll presume you meant string.count() - which is depreciated in favour of the method on string objects.

The difference is that str.count() is a method on string objects, while string.count() is a function in the string module.

>>> "test".count("t")
2
>>> import string
>>> string.count("test", "t")
2

It's clear why the latter has been deprecated (and removed in 3.x) in favour of the former.

回答2:

Use len():

>>> len('abcd')
4

回答3:

This works fine in 2.7.3

>>> strs='aabbccddaa'
>>> strs.count('a')
4

回答4:

Without using count you can do this:

def my_count(my_string, key_char):
    return sum(c == key_char for c in my_string)

Result:

>>> my_count('acavddgaaa','a')
5

回答5:

The other way can be

strs.__len__()

来源：https://stackoverflow.com/questions/10385902/what-is-the-preferred-way-to-count-number-of-ocurrances-of-certain-character-in