Logical Disjunct with PyDatalog

Question

I don't seem to be able to write (pseudo-code): Print X and Y for all X,Y where X==True and Y==True or Y==False

>>> from pyDatalog import pyDatalog
>>> pyDatalog.create_terms('X,Y')
>>> print((X==True)
X   
----
True
>>> print((X==True) & (Y==True))
X    | Y   
-----|-----
True | True

The goal is to write something like:

>>> print((X==True) & ((Y==True) or (Y==False)))
X    | Y   
-----|-----
True | True
True | False

Instead, this prints out exactly what the previous command returned.

How can I do this?

score 1 · Answer 1 · answered Jan 24 '16 at 19:37

I'm still somewhat new to pyDatalog, but my understanding is that disjunctions should be split into multiple lines. So your code would be come (the admittedly somewhat unenlightening):

from pyDatalog import pyDatalog
pyDatalog.create_terms('X,Y')

print(((X==True) & ((Y==True))))
print(((X==True) & ((Y==False))))

score 1 · Answer 2 · edited Apr 13 '16 at 00:56

If it means to go through set of Boolean values for both X and Y, and print the result of X && Y, this should work:

from pyDatalog import pyDatalog

allValues = [True, False]

pyDatalog.create_terms('result, X, Y, R, table')

(result[X, Y] == True) <= (X == True) & (Y == True)
(result[X, Y] == False) <= (X == False)
(result[X, Y] == False) <= (Y == False)

table(X, Y, R) <= (X._in(allValues)) & (Y._in(allValues)) & (R == result[X, Y])

print(table(X, Y, R))

This is the output:

X     | Y     | R    
------|-------|------   
False | True  | False   
False | False | False  
True  | True  | True  
True  | False | False

Logical Disjunct with PyDatalog

2 Answers2