how to count periods latters in string python

Question

i need to count how many periods (points) appear in a string.

for example:

str="hellow.my.word."

the code should return 3.

I tried to use the following function but it returns the length of the string.

 num=str.count('.')

What is the correct way to do it?

Other answers that I have seen appear to use iterations. Using iterations is not appropriate for this purpose. Use regular expressions instead: `len(re.findall("(\.)", my_string))` — Pouria, May 08 '16 at 14:17

score 2 · Answer 1 · answered May 08 '16 at 14:04

2

Use variable name other than str(str is built-in).

Secondly:

string = "hellow.my.word."
num=string.count('.') # num=3 ...THIS WORKS

answered May 08 '16 at 14:04

SivNiz

score 1 · Answer 2 · answered May 08 '16 at 14:00

1

Use a for comprehension to iterate over the string:

Also, don't use str as a variable name, it's a built-in function in python.

string="hellow.my.word."

sum([char == '.' for char in string])  # Returns 3

EDIT

Regarding @niemmi's comment, apparently this is possible using string.count('symbol'):

string.count('.') # returns 3

answered May 08 '16 at 14:00

Anthony E

FWIW, although `str` is certainly a callable it's not really a function. `str` is a type (IOW, a class), so when you call it it creates a new string instance. – PM 2Ring May 08 '16 at 16:25

score 1 · Answer 3 · answered May 08 '16 at 14:01

1

One possible solution is to filter out other characters than . and measure the length of resulting list:

len([1 for c in string if c == '.'])

answered May 08 '16 at 14:01

enedil

3 Answers3