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There are 3 logical operators in Python: `and`

, `or`

, and `not`

. The meaning of these operators is similar to their meaning in English.

```
3 < 4 and 4 > 1
```

It returns `True`

```
x % 2 == 0 or x % 4 == 0
```

It returns `True`

if either of the conditions is true, i.e. if the number x is divisible by `2`

or `4`

.

The `not`

operator negates a boolean expression, so,

```
not (a > b )
```

It returns `True`

if a > b is false i.e. if a is less than or equal to b.

Generally, the operands of the logical operators should be boolean expressions, but Python is not very strict. Any nonzero number is interpreted as `True`

.

```
23 and True
```

It returns `True`

.

While processing a logical expression such as `x >= 2 and (x/y) > 2`

, Python evaluates the expression from left to right. Because of the definition of `and`

, if x is less than 2, the expression `x >= 2`

is `False`

and so the whole expression is `False`

regardless of whether `(x/y) > 2`

evaluates to `True`

or `False`

.

So, when there is nothing to be profitable by evaluating the rest of a logical expression, it stops its evaluation and does not do the computations in the rest of the logical expression. When the evaluation of a logical expression stops because the overall value is already known, it is called **short-circuiting** the evaluation.

Short-circuiting helps in creating a guard. For eg,

```
if y != 0 and x/y:
print("Correct")
```

Here, `y != 0`

acts as a guard to ensure that we only execute `(x/y)`

if y is non-zero because division by 0 would give an error.

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