Branching statements in Python

Comparison operators
if-else statement

1. Comparison operators

The common comparison operators:

Operator	Meaning	Example
>	greater than	5 > 4 is true
<	less than	4 < 5 is true
>=	greater than or equal	4 >= 4 is true
<=	less than or equal	3 <= 4 is true
==	equal to	1 == 1 is true
!=	not equal to	1 != 2 is true
and	and	a > 4 and a < 10
or	or	a == 1 or a == 4

2. if-else statement

No ADS

if is a statement which checks a certain condition in Python. For example: If a> b, then do something ....

Syntax:

if condition_1 :
    # Do something

elif condition_2 :
    # Do something

elif condition_N:
    # Do something

else :
    # Do something

The program checks the condition from top to bottom until it encounters a condition that is true, and run this block and the program does not check the remaining conditions in the branching structure.

Example (if - else):

ifElseExample.py

option = 5 

if option == 1:
    print("Hello")
else :
    print("Bye!")

Output:

Bye!

Example (if - elif - else):

ifElseExample2.py

print("Please enter your age: \n")
# Declare a variable to store the user input from the keyboard.
inputStr =  input()

# int(..) function convert string to integer
age = int(inputStr)
# Print out your age
print("Your age: ", age)

# If age < 80 then ..
if (age < 80) :
    print("You are pretty young")
# Else if age between 80, 100 then
elif (age >= 80 and age <= 100) :
    print("You are old")
# Else (Other case)
else :
    print("You are verry old")

Running the example:

No ADS

Branching statements in Python

1. Comparison operators

2. if-else statement

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