Creating a Truth Table for Any Expression in Python
I Am Attempting to Create a Program That When Run Will Ask for the Boolean Expression, the Variables and Then Create a Truth Table for Whatever Is Entered. I...
I am attempting to create a program that when run will ask for the boolean expression, the variables and then create a truth table for whatever is entered. I need to use a class and this is what I have so far. I am not sure where to go from here.
from itertools import product
class Boolean(object):
def __init__(self, statement, vars):
self.exp = statement
self.vars = vars
def __call__(self, statement, vars):
def main():
expression = raw_input('Give an expression:')
vars = raw_input('Give names of variables:')
variables = vars.split(' ')
b = Boolean(expression, variables)
if __name__ == "__main__":
main()
3 Answers
I have a library that does exactly what you want! Check out the github repo or find it here on pypi.
The readme describes how everything works, but here's a quick example:
from truths import Truths
print Truths(['a', 'b', 'x', 'd'], ['(a and b)', 'a and b or x', 'a and (b or x) or d'])
+---+---+---+---+-----------+--------------+---------------------+
| a | b | x | d | (a and b) | a and b or x | a and (b or x) or d |
+---+---+---+---+-----------+--------------+---------------------+
| 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 0 | 0 | 0 | 1 | 0 | 0 | 1 |
| 0 | 0 | 1 | 0 | 0 | 1 | 0 |
| 0 | 0 | 1 | 1 | 0 | 1 | 1 |
| 0 | 1 | 0 | 0 | 0 | 0 | 0 |
| 0 | 1 | 0 | 1 | 0 | 0 | 1 |
| 0 | 1 | 1 | 0 | 0 | 1 | 0 |
| 0 | 1 | 1 | 1 | 0 | 1 | 1 |
| 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1 | 0 | 0 | 1 | 0 | 0 | 1 |
| 1 | 0 | 1 | 0 | 0 | 1 | 1 |
| 1 | 0 | 1 | 1 | 0 | 1 | 1 |
| 1 | 1 | 0 | 0 | 1 | 1 | 1 |
| 1 | 1 | 0 | 1 | 1 | 1 | 1 |
| 1 | 1 | 1 | 0 | 1 | 1 | 1 |
| 1 | 1 | 1 | 1 | 1 | 1 | 1 |
+---+---+---+---+-----------+--------------+---------------------+
Hope this helps!
You could simply define any boolean function right in python.
consider the following example:
def f(w,x,y,z):
return (x and y) and (w or z)
I've wrote a snippet that takes any function f, and returns its truth table:
import pandas as pd
from itertools import product
def truth_table(f):
values = [list(x) + [f(*x)] for x in product([False,True], repeat=f.func_code.co_argcount)]
return pd.DataFrame(values,columns=(list(f.func_code.co_varnames) + [f.func_name]))
Using this will yield (in a nicely formatted html if you're using IPython Notebook):
truth_table(f)
w x y z f
0 False False False False False
1 False False False True False
2 False False True False False
3 False False True True False
4 False True False False False
5 False True False True False
6 False True True False False
7 False True True True True
8 True False False False False
9 True False False True False
10 True False True False False
11 True False True True False
12 True True False False False
13 True True False True False
14 True True True False True
15 True True True True True
Cheers.
You probably want to do something like this:
from itertools import product
for p in product((True, False), repeat=len(variables)):
# Map variable in variables to value in p
# Apply boolean operators to variables that now have values
# add result of each application to column in truth table
pass
But the inside of the for loop is the hardest part, so good luck.
This is an example of what you would be iterating over in the case of three variables:
>>> list(product((True, False), repeat=3))
[(True, True, True), (True, True, False), (True, False, True), (True, False, False), (False, True, True), (False, True, False), (False, False, True), (False, False, False)]
Sarah Jenkins is a veteran tech journalist with over 12 years of experience covering artificial intelligence, mobile innovations, and digital ethics. Her insights have appeared in leading technology publications worldwide.
