Removing punctuation and lowercasing a string

Question

I am very fresh to python. As part of an assignment, I've written the following code to remove punctuation from a string and convert it to lowercase.

import string
words = "Dave, Laura, Maddy, Dave, Laura, Maddy, Dave, Laura, Dave";
translation = str.maketrans("","", string.punctuation);
new = words.translate(translation);
lower = new.lower();

However, this seems crude to me and I feel like I can accomplish my task with fewer function calls/less code. Does anyone have any suggestions as to how I could do this?

• David Tamrazov: I mean I've done the tasked asked of me no problem, and this is maybe a quarter of it. I'm simply asking if theres a cleaner method to it. This'll suffice just fine for my class.
• TheCoffeeCup: This question is on the line for off-topic category right now, and I am not sure what to do with it. It seems to be unfinished, so I will vote to close this question.
• anon: This doesn't look too off-topic to me. It's fully functional code, and David is asking for improvements.
• Legato: There is absolutely nothing wrong with this. OP has accomplished his task, and is asking how could it be better. This is 100% what CR is about. We wouldn't have a homework tag if this wasn't acceptable.
• 200_success: There is a bit of a mess, though. The original title mentioned splitting the string, which the code never actually does. Yet @PatrickS has incorporated splitting into his answer.

Answer 1

To reduce the number of lines and statements for your problem note:

• For your input format splitting on spaces and removing punctuation can be a single operation: split on , (comma-space).
• You don't need to use a (new) variable for every intermediate step.

String methods can be chained. Here words is first made lower-case and then splitis called.

words = "Dave, Laura, Maddy, Dave, Laura, Maddy, Dave, Laura, Dave";
result = words.lower().split(", ")

Alternatively you can use a list comprehension. Here the words are split and then every word of the intermediate result is made lower-case.

words = "Dave, Laura, Maddy, Dave, Laura, Maddy, Dave, Laura, Dave";
result = [word.lower() for word in words.split(", ")]

• kushj: Your answer returns a result, while I think OP just wants a string as output?
• David Tamrazov: Oh brilliant, that's so much cleaner. Thats exactly the kind of revision I was looking for, thanks @PatrickS.
• David Tamrazov: @kushj No I actually need a string to work with.

Answer 2

Instead of just import string you could get the punctuation list directly:

from string import punctuation
words = "Dave, Laura, Maddy, Dave, Laura, Maddy, Dave, Laura, Dave"
translation = str.maketrans("", "", punctuation)

I'd also remove the semicolons. Python doesn't need them to know when a line of code ends since it uses newlines instead (there are exceptions, but none here) so you can remove them.

Answer 3

Here's how I would do it:

Mesh the following operations into a single line:

 - step 1: str.split(",") # split string into a list, remove "," chars
 - step 2: "".join(lst) # join lst items with "" in between
 - step 3: str.lower() # turn string to lowercase

Your desired code:

res = "".join(words.split(",")).lower()

p.s. best I am aware, join() is faster than list comprehension.