Removing punctuation in lists in Python

Question

Creating a Python program that converts the string to a list, uses a loop to remove any punctuation and then converts the list back into a string and prints the sentence without punctuation.

punctuation=['(', ')', '?', ':', ';', ',', '.', '!', '/', '"', "'"]

str=input("Type in a line of text: ")

alist=[]
alist.extend(str)
print(alist)

#Use loop to remove any punctuation (that appears on the punctuation list) from the list

print(''.join(alist))

This is what I have so far. I tried using something like: alist.remove(punctuation) but I get an error saying something like list.remove(x): x not in list. I didn't read the question properly at first and realized that I needed to do this by using a loop so I added that in as a comment and now I'm stuck. I was, however, successful in converting it from a list back into a string.

Solution 1

import string
punct = set(string.punctuation)

''.join(x for x in 'a man, a plan, a canal' if x not in punct)
Out[7]: 'a man a plan a canal'

Explanation: string.punctuation is pre-defined as:

'!"#$%&\'()*+,-./:;<=>?@[\\]^_`{|}~'

The rest is a straightforward comprehension. A set is used to speed up the filtering step.

Solution 2

I found a easy way to do it:

punctuation = ['(', ')', '?', ':', ';', ',', '.', '!', '/', '"', "'"]
str = raw_input("Type in a line of text: ")

for i in punctuation:
  str = str.replace(i,"")

print str

With this way you will not get any error.

Solution 3

punctuation=['(', ')', '?', ':', ';', ',', '.', '!', '/', '"', "'"]
result = ""
for character in str:
   if(character not in punctuation):
       result += character
print result