Having a really silly problem. I'm iterating over a string and removing all non-alphabetical characters. The problem is that when I remove them, the length of the string decreases and my loop crashes because I go out of bounds.
for x in s:
if x.isalpha() == False:
s = s.replace(x, "")
Use filter!
s = filter(str.isalpha, s)
str.join call will be needed.Use a regex!
import re
regex = re.compile('[^a-zA-Z]') #Create a regex that allows on only A-Z and a-z
regex.sub('', s) #This will return the string, stripped of non alphabetical characters
The trick is to loop from end to front if you insist to use loop...
This is the useful trick to handle the length change.
for x in s[::-1]:
if x.isalpha() == False:
s = s.replace(x, "")
Edit: I forgot to mention, to reverse a string, you can do s[::-1]
s, it will work even if you delete s.A list comprehension is the most Pythonic way to do this.
s = ''.join([x for x in s if x.isalpha()])
The list comprehension builds a list containing alpha characters only, and join() returns a string of those characters.
sreally is a string, this will not crash, whatever that means. The code you posted will work and produce the intended result both on Python 2 and Python 3. It is however very inefficient.