I am new to python. I have tested my interpreter using following code,
In [1]: 2 and 3
Out[1]: 3
In [2]: 3 and 2
Out[2]: 2
In [3]: 3 or 2
Out[3]: 3
In [4]: 2 or 3
Out[4]: 2
In the above, take 2=0010 and 3=0011. the result is,
+ 0010
0011
----
0010=2
But Out[1] gave the 3(not exact) and out[2] gave the 2(exact).
What is the difference in two cases?
You are using boolean logic or and and, which short-circuit (return the first operand for which the outcome of the operator is fixed).
You are looking for the binary bitwise operators instead, | and &:
>>> 0b10 & 0b1
0
>>> 0b10 | 0b1
3
The or operator returns the first operand if it is true-y (not empty or numeric 0), the second operand otherwise, the and operator returns the first if it is false-y, the second operator otherwise. This is why you see 3 and 2 return 2, and 3 or 2 return 3. Both 2 and 3 are non-zero, so true in a boolean context.
Using 0 as a false value you'd see:
>>> 3 and 0
0
>>> 3 or 0
3
>>> 0 and 3
0
>>> 0 or 3
3
False, None, 0, and any object obj where len(obj)==0, for example "", [], () and {}. All other objects are considered to be "true". Here are a few examples using the logical operators: [] or 5 == 5, [] or () == (), True and None == None, [1,2,3] or False == [1,2,3], etc.
None they can all be reduced to 'empty' or 'numeric 0'.int(False)==0 and int(None)==0. The precise rules are available here: docs.python.org/2/library/stdtypes.html#truth-value-testingint(None) is just the int() constructor with no argument; True == 1 is True, as is False == 0, but None == 0 is False. That's because the bool type is a subclass of int.You are looking for the bitwise operators,
>>> 2 & 3
2
>>> 2 | 3
3
By just doing 2 and 3 you are evaluating 2, which is True, then 3 (also True) and Python returns that second number. So you get 3.
With 2 or 3, it short-circuits and just returns 2 since 2 is True.
You are looking for the bitwise and, &.
and and or are boolean operators in Python, whereas & and | are bitwise operators.
Example -
>>> 2 and 3
3
>>> 2 & 3
2
use &, and is boolean AND in python:
>>> 2 & 3
2
>>> 3 & 2
2
