I'm trying to remove punctuations from a tokenized text in python like so:
word_tokens = ntlk.tokenize(text)
w = word_tokens
for e in word_tokens:
if e in punctuation_marks:
w.remove(e)
This works somewhat, I manage to remove a lot of the punctuation marks but for some reason a lot of the punctuation marks in word_tokens are still left. If I run the code another time, it again removes some more of the punctuations. After running the same code 3 times all the marks are removed. Why does this happen?
It doesn't seem to matter whether punctuation_marks is a list, a string or a dictionary. I've also tried to iterate over word_tokens.copy() which does a bit better, it almost removes all marks the first time, and all the second time. Is there a simple way to fix this problem so that it is sufficient to run the code only once?
You are removing elements from the same list that you are iterating. It seems that you are aware of the potential problem, that's why you added the line:
w = word_tokens
However, that line doesn't actually create a copy of the object referenced by word_tokens, it only makes w reference the same object. In order to create a copy you can use the slicing operator, replacing the above line by:
w = word_tokens[:]