Can somebody help me make the code below smarter and free of redundancy? The code does exactly what I want, but I believe there are many redundant loops and arrays.

from collections import Counter
import csv
import re

with open("/Users/max/train.csv", 'r') as file:
  reviews = list(csv.reader(file))

def get_texts(reviews, score):
  texts = [] 
  texts.append([r[0].lower() for r in reviews if r[1] == str(score)]) ; 
  return texts

def getWordListAndCounts(text):
  words = []  
  for t in text:
      for tt in t:
        for ttt in (re.split("\s+", str(tt))):
  return Counter(words)

negative_text_list = get_texts(reviews, -1)
positive_text_list = get_texts(reviews, 1)

negative_wordlist_counts = getWordListAndCounts(negative_text_list)

positive_wordlist_counts = getWordListAndCounts(positive_text_list)

print("Negative text sample: {0}".format(negative_text_list))
print("Negative word counts: {0}".format(negative_wordlist_counts))
print("Positive text sample: {0}".format(positive_text_list))
print("Positive word counts: {0}".format(positive_wordlist_counts))

Sample contents in train.csv are as below.

i like google,1
google is evil,-1
Apple is cute,1
Microsoft booo,-1

2 Answers 2


Your code is actually really good. But:

  • getWordListAndCounts should be get_word_list_and_counts. This is as Python has a style guide called PEP8.

  • You use a ; but for no reason. It's best to never use it.

  • In get_texts you do [].append([...]). This can be: [[...]].

  • In get_texts you have r, it would be better to use review, this makes it easier to read. Also all the ts in getWordListAndCounts.

  • You can make getWordListAndCounts a list/generator comprehension.

  • You seem to mix spaces and tabs. This leads to highly breakable code. (Look at your question)

  • Don't have white space after code. It's really annoying, and violates PEP8.

Overall I would say your code is pretty decent.

I would re-write getWordListAndCounts to this for example:

def get_word_list_and_counts(text):
    # Rename the `t`'s I have no context on what they are.
    return Counter(
        for t in text
        for tt in t
        for ttt in (re.split("\s+", str(tt)))

To remove the [].append, you can use the following if it has to be a list.

def get_texts(reviews, score):
    return [r[0].lower() for r in reviews if r[1] == str(score)]

As no-one has said it:

[[...]] in get_texts seems redundent, adds complexity, and makes the algorithm worse in memory, from \$O(1)\$ with generator comprehensions, to \$O(n)\$.

The way you call the code shows us also that there is potential to reduce the complexity.

getWordListAndCounts(get_texts(reviews, 1))

To show the change to get \$O(1)\$:

def get_texts(reviews, score):
    return (
        for review in reviews
        if review[1] == str(score) # use ferada's change

def get_word_list_and_counts(text):
    return Counter(
        for line in text
        for word in (re.split("\s+", line))

The above shows you can clearly see it's capable to be in a single function, if you wish for it. And remove one of the fors in the get_word_list_and_counts.

It as one function would look like this:

def get_word_list_and_counts(reviews, score):
    return Counter(
        for review in reviews
        if review[1] == str(score)
        for word in re.split("\s+", review[0].lower())

That with ferada's change is probably the smallest and most concise you'll get it. Also the second for statement will only run if the if is true.

  • \$\begingroup\$ Thanks Joe, quite helpful. Actually in get_texts, I am trying to avoid getting [[...]] . How can I change [].append([...]). ? Then I will be able to reduce the number of for loops in getWordListAndCounts. \$\endgroup\$
    – Max
    Oct 9, 2015 at 12:18
  • 1
    \$\begingroup\$ @Max [].append([...]) is the same as [[...]]. You can remove the outer [], so that it becomes [...]. Or as I put in the answer, (...), if memory is a concern. (Replace ... with r[0].lower() for r in reviews if r[1] == str(score)) \$\endgroup\$
    – Peilonrayz
    Oct 9, 2015 at 12:23

I agree, looks good. It would really help to have some sample input btw.

  • I can't tell whether either of the strs in get_word_list_and_counts are necessary. Even with something like get_word_list_and_counts([["hue hue hue"], [1, 2]]) I get a result like Counter({'hue': 3, '2': 1, '1': 1}), which is the same as if the [1, 2] was instead "1 2".

The following complaints are mostly micro-optimisations, but it wouldn't hurt to keep them in mind for future projects.

  • get_texts is repeatedly calling str, that can be avoided by storing the string representation or passing in a string in the first place.

    def get_texts(reviews, score):
        score = str(score)
        return [[r[0].lower() for r in reviews if r[1] == score]]
  • There's no reason not to do the whole process in a loop while reading from the CSV file. That will keep memory consumption down and make the program work even on much bigger files. E.g.:

    with open("...") as file:
        for line in csv.reader(file):
            # split line
            # update counter

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