Course Content
Introduction to Python
3. Conditional Statements
Introduction to Python
Combining Conditions
In Boolean logic, two fundamental operators are OR and AND. What do they represent?
The OR operator checks if either of the conditions is true and returns True
if so; otherwise, it returns False
.
The AND operator ensures both conditions are true before returning True
. If not, it returns False
.
In Python, to combine conditions, use the and
& or
operators (always in lowercase). For example:
condition1 and condition2
yieldsTrue
only when both conditions areTrue
.condition1 or condition2
givesTrue
if at least one condition isTrue
.
Note
You can also chain more than two conditions using these operators. Employ parentheses to clarify the order of operations.
As an illustration, consider these conditions:
- Whether
2
exceeds1
and if"bbb"
isn't the same as"aaa"
. - If the character with index
2
in the string"my string"
is either"y"
or"s"
.
Code Description
2 > 1 and "bbb" != "aaa"
involves two conditions connected by the and
operator. The first condition 2 > 1
is true because 2 is greater than 1. The second condition "bbb" != "aaa"
is also true because the strings "bbb" and "aaa" are not equal. Since both conditions are true and they are connected by and
, the entire expression evaluates to true.In the second line,
"my string"[2] == "y" or "my string"[2] == "s"
checks two conditions connected by the or
operator. The expression "my string"[2]
refers to the third character of the string "my string", which is " ". The first condition "my string"[2] == "y"
is false. The second condition "my string"[2] == "s"
is false, and since both of the conditions is false and they are connected by or
, the overall expression evaluates to false.
How should we interpret the outcomes? The initial print()
issues a True
response since both 2 > 1
and "bbb" != "aaa"
hold true. The following print()
yields False
because the character at index 2
is neither 'y'
nor 's'
(it's actually a space).
Note
If you wish to reverse a boolean value, employ the
not
operator. For instance,not 1 == 1
results inFalse
because1 == 1
isTrue
, and we've negated that toFalse
.
What output does the subsequent code produce?
Select the correct answer
Code Description
print(0 > 10 and 5 > 2)
: This prints False
because, while 5 > 2
is true, 0 > 10
is false. The and
operator requires both conditions to be true, but since one is false, the overall expression is false.print(2*2 == 5 or 1+1 != 3)
: This prints True
because 2*2 == 5
is false, but 1+1 != 3
is true. The or
operator only requires one of the conditions to be true for the overall expression to be true.
Everything was clear?