A statement when executed, on the basis of the result of a condition given in the program code known as the conditional statement
firstly In python, there are different forms of if statement they are
- if
- if-else
- if-elif-else
we have discussed if and if-else in detail
If-elif-else condition
In some cases, we want to check the condition at the else case also, ie, condition given in
the form of else if. To help in such conditions, Python provides if-elif and if-elif-else
statements. let’s discuss more clearly but it in the following content
Syntax
if <conditional expression> :
statement
[statements]
elif <conditional expressions :
statement
[statements]
Explanation
If keyword should be given followed by the condition and ending with a colon :
Firstly the if condition will check for the condition given to it and if the given condition satisfied then it will execute the statements given inside
how if-elif works
An if statement checks for a particular condition and
if the condition results to be true,
then a bunch of statements or set-of-statements below them executed.
in case the condition is false, it will check the conditions given in the elif
if it is also satisfied then it will execute the statements given below the elif condition
in case the elif condition also fails then it will move to the else part and then it will proceed further
Flowchart of Elif
EXAMPLE
a=55.25
if a > 0:
print("Positive number")
elif a == 0:
print("Zero")
else:
print("Negative number")
Output
positive number
Explanation
Firstly we are checking if the condition is true or not
yes a is greater than 0 so it will come outside the loop and starts executing the statements given
in this example, we have given the statements to print if it is greater than zero as positive
so it printed positive number
Nested If (elif-else) condition
In some cases we need to check additional conditions. In such situations, Python also
supports a nested-if form. The nested if is an if that has another if in its if’s body or in elif’s
body or in its else’s body.
Syntax
if <conditional expression1> :
if <conditional expression2> :
statement
[statements]
elif <conditional expressions :
statement
[statements]
else
statement
[statements]
else <conditional expressions :
statement
[statements]
how if-elif works
An if statement checks for a particular condition and
if the condition results to be true,
then again it will check for the inner if condition
if it fails it will check for inner elif below it
even it also fails then inner else statements will
be executed
in case if the condition fails then it will move to the else part and then it will proceed further
Flowchart of Nested if
EXAMPLE
a = float(input("Enter a number: "))
if a >= 0:
if a == 0:
print("Zero")
else:
print("Positive number")
else:
print("Negative number")
Output
Enter a number: -9 Negative number
Explanation
Firstly we are checking if the condition is true or not
no its a is lesser than 0 so it will come outside to else statement and starts executing the statements given
in this example, we have given the statements to print if it is lesser than zero as negative
so it printed negative number
