Question

In Python, I’m trying to add elements from an array into a string using “%s”.

However, at compile time, the size of the array, and the string i’m interpolating into, are unknown. The idea is that i’m making a madlibs type script which pulls the text from a separate file.

Current code:

from sys import argv

script, input = argv

infile = open(input)

madlibs = eval(infile.readline())
words = []

for word in madlibs:
    words.append(raw_input("Give me a %s: " % word))

print infile.read() % words

So, the first line of the input file contains the madlib questions, and the subsequent text has the story. Here is the example input file i’m using:

["noun", "verb", "verb", "noun"]
There once was a %s named Bill.
He liked to %s all the time.
But he did it too much, and his girlfriend got mad.
She then decided to %s him to get back at him.
He died. It's a sad story.
They buried him. And on his tombstone, they placed a %s.

So, in an ideal world,

print infile.read() % words 

would work, as it would just interpolate the elements in “words” into the string pulled from the file.

However, it doesn’t, and i’m out of ideas. Any help?

Answer 1

Make sure words is a tuple:

print(infile.read() % tuple(words))

By the way, a MadLib sometimes repeats the same supplied word. It would therefore be easier to make words a dict instead of list. You could then do something like this:

words = {
    'man' : 'Bill',
    'store' : 'bar',
    'drink' : 'beer',
    'owner' : 'bartender',
    'action' : 'drink',
    }

text = '''
{man} walks into a {store} and orders a {drink}.
The {owner} asks {man} what he would like to {action}
'''

print(text.format(**words))

which yields

Bill walks into a bar and orders a beer.
The bartender asks Bill what he would like to drink