This function's goal is to reduce the length of a sentence to exactly max_length characters by cutting each word in the sentence to a length of minimum 4 characters, if cutting each word to 4 characters isn't enough the the sentence is returned anyway.

All sentences are free of special characters and words are separated by spaces.

Here is the function:

def cut_everything(sentence, max_length):

    """

    reduces each word in sentence to a length of 4



    :type sentence: string

    :param sentence: the sentence to cut

    :type max_length: int

    :param max_length: the length to which the sentence will be reduced

    """

    words = sentence.split()

    for index, word in enumerate(words):

        word_length = len(word)

        if word_length > 4:

            to_cut = len(sentence) - max_length

            to_keep = word_length - to_cut

            if to_keep < 4:

                to_keep = 4

            words[index] = word[:to_keep]

            sentence = ' '.join(words)

            if len(sentence) <= max_length:

                break



    return sentence

My main concern for this review is performance, but any readability comment is appreciated

Review

• 
  

  Magic numbers

  
  
  

  4 is a magic number, it is best to assign these to a variable name, that way it is more clear what this number means

  
  
  

  numbers don't have names, variables do

  
  
  

  MAX_WORD_LENGHT = 4
  
  

  
  


• 
  

  Use built-ins when possible

  
  
  

  
  

  to_keep = word_length - to_cut
  
  if to_keep < 4:
  
  to_keep = 4
  
  

  
  

  
  
  

  Can be replaced with the max builtin

  
  
  

   to_keep = max(word_length - to_cut, 4)
  
  

  
  


• 
  

  Add tests

  
  
  

  That way it becomes easy to check after a change if the function still works

  
  

Alternative

I went a slightly different route,

Instead of joining after each word, I calculate the chars we need to cut beforehand

So we can keep a variable that will hold the amount of chars we still need to cut to reach our target

And only at the return join the words

import doctest



MAX_WORD_LENGHT = 4



def cut_everything(sentence, max_length):

    """

    reduces each word in sentence to a length of 4



    :type sentence: string

    :param sentence: the sentence to cut

    :type max_length: int

    :param max_length: the length to which the sentence will be reduced



    >>> cut_everything('foo bar foooobar', 16)

    'foo bar foooobar'



    >>> cut_everything('foo bar foooobar', 8)

    'foo bar fooo'



    >>> cut_everything('foo bar foooobar baaarfoo', 20)

    'foo bar fooo baaarfo'



    >>> cut_everything('fooooooo baaaaaaar foooobar baaarfoo', 2)

    'fooo baaa fooo baaa'

    """

    words = sentence.split()

    chars_to_cut = len(sentence) - max_length

    for index, word in enumerate(words):

        if chars_to_cut == 0:

            break

        word_length = len(word)

        if word_length > MAX_WORD_LENGHT:

            to_keep = max(word_length - chars_to_cut, MAX_WORD_LENGHT)

            words[index] = word[:to_keep]

            chars_to_cut -= word_length - to_keep

    return ' '.join(words)



if __name__ == '__main__':

    doctest.testmod()