All programming language has if statements that allow controlling the flow of the program.
With this, you can execute your code only when the condition is true or false.
In the tutorial, I show how you can use if statements in your program with an example in Python.
Contents
1. if statement
if statement, first checks the condition if it is true then executes the block of code otherwise skip it and execute the next statement.
Syntax –
if condition : # true statement # next statement
Example –
num = 4
if num%2 == 0 :
print("Even number")
print("num : ",num)
Output
Even number num : 4
2. if else statement
If statement only executes when condition return true if the condition is false for handling that use else statement with if. It executes when the condition is false.
Syntax –
if condition : # true statement else: # false statement # next statement
Example –
num = 5
if num%2 == 0 :
print("Even number")
else:
print("Odd number")
print("num : ",num)
Output
Odd number num : 5
3. elif statement
elif statement allows us to define multiple if statement. If the condition is not true then again check with other conditions using elif. You can define multiple elif statements but only one else statement.
Syntax –
if condition: # true statement1 elif condition: # true statement2 elif condition: # true statement3 . . . else: # false statement # next statement
Example –
num = 30
if num == 10:
print("If statement1")
elif num == 20:
print("If statement2")
elif num == 30:
print("if statement3")
else:
print("Else statement")
print("num : ",num)
Output
if statement3 num : 30
In the above program, I defined multiple if statements using elif statement. Only one if statement will execute when you run the above program. It checks to if statement until true condition not found. If found valid condition then execute the block of code and then go to the next block of code.
4. Nesting
In a program in some cases, require to check another condition if one is true. For this purpose, generally use nested if statement using this you can define if statement within another if statement. Same you can do with else.
Syntax –
if condition:
# true statement
if condition:
# true statement
else:
# false statement
else:
if condition:
# true statement
else:
# false statement
# next statement
Example –
num = 30
if num == 10:
print("If statement1")
elif num == 20:
print("If statement2")
elif num == 30:
print("if statement3")
else:
print("Else statement")
print("num : ",num)
Output
if statement3 num : 30
