I need to decompose a string into Python, separating letter and numbers, and perform the sum of these numbers. For example:
string ="96h11k"
From this string I need to extract the numbers 9, 6, 1, 1 and add them: 9 + 6 + 1 + 1 = 17. Actually, the sum is between the digits.
In Python, you can iterate over a string as if it were a list:
>>> for ch in string:
... print(ch)
...
9
6
h
1
1
k
In above, each iteration ch will be a string of 1 character. To see if this character is numeric or not, you can use ch.isdigit() . To convert it to an integer, you can use int(ch) . So just add it all up:
soma = 0
for ch in string:
if ch.isdigit():
soma += int(ch)
print(soma)
A more concise way to do this is by using list comprehensions (or generating expressions), and the sum() (sum). For an example, see Maniero's answer .
According to this answer in SO could use functions ready for this:
def sum_digits(digit):
return sum(int(x) for x in digit if x.isdigit())
See running on ideone . And no Coding Ground . Also I put GitHub for future reference .
In this way you are using the sum() function whose data is generated through a list understanding where each element of the list (a string is a list of characters) is individually decomposed. >
In this case you are taking the parameter digit and analyzing each of its elements, that is, each of the characters. If the element is taken as a numeric digit (function isdigit() ) it will be delivered to the algorithm of the sum() function that knows how to add them.
You can also do it manually as shown by mgibsonbr response .
my_string = "96h11k"
soma = sum([int(i) for i in my_string if i.isdigit()])
-------- EDIT ---------
Now that I've seen that my answer is identical to Maniero ...
For the answer is not completely useless, here's a look at generator expressions .
fim=int(input("Digite o valor de n: "))
string = str(fim)
soma = 0
for ch in string:
if ch.isdigit():
soma += int(ch)
print(soma)