Getting random lines from txt files

   Working on my whispering wall the other day, I wanted a much better way to 'randomly' select lines it would give back to the user.  random.shuffle seemed like a better way.

Thanks again to the interwebs for the tools to search up the things I need.


   I wasn't sure how to properly handle the global aspect of 'LINE_GET' for this piece. LINE_GET is going to be the integer I use to select a number from the list that is made, that is then in turn used to get a 'random' line from my txt file.

   In my whispering wall, this variable would be a part of the WhisperingWall class. And it's alteration would be internal, but for the sake of making this blog post I needed it to be easy to access and alter.  And globals, well, everyone says they are bad. I may be writing completely horrible code for that part. I am not sure, but hey, I didn't use a global!  kinda... sorta....

Anyway!
two methods, a class(**cough global**), and a system argument (sys.argv),  that can more randomly select a line from a txt file and return it.

Here's the code: 

####### random_script_picker.py  ######


#!usr/bin/python3
import random
import sys

text_file = sys.argv[1]
#LINE_GET = 0
class NotGlobal(object):
    line_get = 0

def create_script_line_order(somescript):
    """ make a list with randomized order of line numbers from script
        using random's shuffle."""
     count = None
    #print(somescript)  I do love print statements.
    try:    #if txt file is empty, i will not be created
        with open(somescript) as f:
            for i, l in enumerate(f):
                pass
            # if i is not created, this is an UnboundLocalError
            count = i
    except:
        # Empty will be returned and get_script_line will call ValueError
        return "EMPTY"

    if count != None:
        first_list = []
        # create a list with all line numbers in it
        for x in range(1, i):
            first_list.append(x)
        # shuffle those items:
        random.shuffle(first_list)

    return first_list

def get_script_line(arg):
      """ Chooses a random script line to give back to user """
     #print(LINE_GET.line_get)

      if arg.endswith('txt'):
          order = create_script_line_order(arg)
      else:
          # when order is None, a Value error will be raised in else clause
          order = None

      if order == "EMPTY":
          print("***txt file is empty***  \n\t", arg)
          raise ValueError

      elif order != None:
          if LINE_GET.line_get >= len(order):
              LINE_GET.line_get = 0
          get_line = order[LINE_GET.line_get]
          with open(arg) as f:
              lines = f.readlines()
              x = int(get_line)
              #print(lines[x])
              LINE_GET.line_get += 1
              return lines[x]

      else:

          print("file must be a .txt for order to be created")
          print("arg passed in = ", arg)
          raise ValueError

LINE_GET = NotGlobal()

# to show it working:
for i in range(0, 5):
    x = get_script_line(text_file)
    print("\n", x)

#####   results:   #####
### the text file is a chunk of Monty Pythons Holy Grail I was modifying to
### try and train Wiwa's NLTK pos_tagger with.