Conditionals

What are conditionals?

• In computer science, conditional statements, conditional expressions and conditional constructs are features of a programming language, which perform different computations or actions depending on whether a programmer-specified boolean condition evaluates to true or false.

What are differnt types of conditional statements in python?

• A few commonly used conditional statements are -
  • if
  • if-else
  • if-elif-else

IF

• One of the basic conditional statements that are used
• It decides whether to execute a given line or skip it depending on condition given to it

Implementation

#following piece of code uses if to check who studies harder
Ankit=10.00 #ofc it is his CGPA
Siddharth=9.80 #not bad right??
if(Ankit>Siddharth): #checks if the given condition is true
	print("Ankit studies harder than Siddharth") #gets executed if the above statement is true
if(Siddharth>Ankit): #checks if the given condition is true
	print("Siddharth studies harder than Ankit")

Output

Ankit studies harder than Siddharth

The indentation here is the key and all the statements that are indented inside the ‘if’ will be executed regardless of the condition

IF-Else

• It is an extension to the if condition
• It helps in deciding which statement to execute when a given condition is true and exucutes other set of them when the condition is false

Implementation

#following piece of code uses if-else to check who studies harder
Ankit=10.00
Siddharth=9.80
if(Ankit>Siddharth): #checks if the given condition is true
	print("Ankit studies harder than Siddharth")
else: #makes the below statements to execute if the above condition is false
	print("Siddharth studies harder than Ankit")

Output

Ankit studies harder than Siddharth

IF-Elif-Else

• It is one step further to if-else
• It can be used to check for multiple conditions and deciding the set of statements that should be executed in case of any condition being true

Implementation

#following piece of code uses if-elif-else to check who studies harder
Ankit=10.00
Siddharth=9.80
if(Ankit>Siddharth): #checks if the given condition is true
	print("Ankit studies harder than Siddharth")
elif(Siddharth>Ankit): #checks if the given condn is true provided all condn above it are false
	print("Siddharth studies harder than Ankit")
else: #makes the below statements to execute if all the above condition is false
	print("Both of them study equally hard")

Output

Ankit studies harder than Siddharth

One can insert any number of elif statements but only one if and else for a given set linked conditions
If in situation we have more then one condition being true the first one from the top is executed and the rest are left unchecked and hence statements skipped

Note

• These conditional statements can be even nested one inside others to the check conditions at various levels

  Implementation

#following piece of code uses nested conditionals to check who studies harder among 3 people
Ankit=10.00
Siddharth=9.80
Chaitya=9.90 #legend for a reason
if(Ankit>Siddharth): #PRIMARY checks if the given condition is true
	if(Ankit>Chaitya): #SECONDARY checks for condition provided primary condn is true
		print("Ankit studies harder than Siddharth and Chaitya both")
	else: #executes if the primary condition is true but the secondary is false
		print("Ankit studies harder than Siddharth but Chaitya studies harder")
else:
	print("Siddharth Studies harder than Ankit")

Output

Ankit studies harder than Siddharth and Chaitya

Here which else and elif corresponds to which if is decided by the indentation and hence it plays a important role and must be taken care of.

• Also a single condition can check multiple condition using logical operators

  Implementation

#following piece of code uses conditionals and logical operators to check who studies harder among 3 people
Ankit=10.00
Siddharth=9.80
Chaitya=9.90
if(Ankit>Siddharth and Ankit>Chaitya): #executes if both the conditions are true
	print("Ankit studies harder than Siddharth and Chaitya both")
elif(Siddharth>Ankit and Siddharth>Chaitya):
	print("Siddharth Studies harder than Ankit and Chaitya")
else:
	print("Chaitya Studies harder than Ankit and Siddharth")

Output

Ankit studies harder than Siddharth and Chaitya