Python summary: truth tables

For determining if something is True or False, we can use the next operators:

  • Comparison: ==, !=, <, =<, >, =>, <>
  • Logical: and, or, not, not and, not or, xor (or exclusive, represented by a caret character [^])
  • Membership: in, not in
  • Identity: is, is not

 

The truth tables is a way to view the result of the these operations. Scheme with the basic logical operators:

AND: only True if both operands is one
0 and 0   False
0 and 1   False
0 and 0   False
1 and 1   True

OR: True when any operand is one
0 and 0   False
0 and 1   True
1 and 0   True
1 and 1   True

NOT: it inverts the value of operand
not 0     True
not 1     False

XOR: True when only one of the operand is true
0 ^ 0     False
0 ^ 1     True
1 ^ 0     True
1 ^ 1     False

 

We must to know the logical operators are short-circuiting, what means if from the first operand it is possible to deduce the result, Python won’t evaluate the second operand; thereby Python saves time. For example, if in AND the first operand is False, it is not necessary to evoaluate the second one, because the result will be False.

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