在python中重用函数

Question

I'm trying to create a very simple application that fills out Mad Libs. To do this I've opened several files that contain my nouns, adjectives, etc.. and created a function that randomly selects a word in the file given. I can use the function fine once, but if I try to use it again on the same file I get a "IndexError: Cannot choose from an empty sequence" problem having to do with the 'random' module. How can I avoid this and the function that I've created. Here is my code:

import random


adjectives = open("data\\adjectives.txt", "r+")
verbs = open("data\\verbs.txt", "r+")
nouns = open("data\\nouns.txt", "r+")
colors = open("data\\colors.txt", "r+")
sports = open("data\\sportsgames.txt", "r+")


def randomize(file):
    return random.choice(file.readlines())

madlib = "One day I was playing {0}. I got bored so I played {1} 
instead.".format(randomize(verbs), randomize(verbs))

print(madlib)

Answer 1

file.readlines() reads the lines starting from the current position in the file. The first time you read the file, it leaves the position at the end of the file. So when you try to use it again, there's nothing left to read, and it returns an empty list.

You need to seek back to the beginning of the file to be able to read it again.

def randomize(file):
    file.seek(0)
    return random.choice(file.readlines())

But it would be simpler if you just read each file once, rather than reading the file each time you want that type of word.

import random

adjectives = open("data\\adjectives.txt", "r+").readlines()
verbs = open("data\\verbs.txt", "r+").readlines()
nouns = open("data\\nouns.txt", "r+").readlines()
colors = open("data\\colors.txt", "r+").readlines()
sports = open("data\\sportsgames.txt", "r+").readlines()

def randomize(file):
    return random.choice(file)

madlib = "One day I was playing {0}. I got bored so I played {1} instead.".format(randomize(verbs), randomize(verbs))

print(madlib)