Python Track · Part 2 of 9

Python Control Flow: if, elif, else and Loops

Learn how Python makes decisions and repeats work with if, elif and else statements, for and while loops, and break and continue.

• Python, control flow statements are used to manage the flow of a program’s execution. They allow you to make decisions, loop through code, and modify the program’s behavior based on conditions.

2.1 Conditional Statements (if, elif, else)

• Conditional statements are used to execute different blocks of code based on whether a specific condition is true or false.

2.1.1 “IF” Condition

• The if statement is used to check a condition. If the condition is true, the code inside the if block is executed.

# if Statement
x = 10
if x > 5:
    print("x is greater than 5")

x is greater than 5

2.1.2 “elif” (short for “else if”)

• The elif statement is used to check additional conditions if the previous if or elif conditions are not met. You can have multiple elif blocks.

# Else Statement
x = 3
if x > 5:
    print("x is greater than 5")
elif x > 0:
    print("x is positive but not greater than 5")

x is positive but not greater than 5

# else & else
x = -2
if x > 5:
    print("x is greater than 5")
elif x > 0:
    print("x is positive but not greater than 5")
else:
    print("x is non-positive")

x is non-positive

2.2 Loops (for, while)

• Loops allow you to repeat a block of code multiple times. In Python, two common types of loops are the for loop and the while loop.

2.2.1 “for” Loop

• It is used to iterate over a sequence (like a list or a range) or any iterable object. The loop executes a specified block of code for each item in the sequence.

# for loop
for i in range(5):
    print(i)

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2.2.2 “while” Loop

• It is used to repeatedly execute a block of code as long as a specified condition is true.

# while loop
x = 0
while x < 5:
    print(x)
    x += 1

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# Iterating Through Data Structures:

my_list = [1, 2, 3, 4, 5]
for item in my_list:
    print(item)

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2.3 Break and Continue Statements

break : The break statement is used to exit a loop prematurely. It is often used in conjunction with conditional statements to terminate a loop based on a specific condition.

# Break statement
for i in range(10):
    if i == 5:
        break
    print(i)

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continue : The continue statement is used to skip the current iteration of a loop and move to the next iteration.

# continue statement

for i in range(5):
    if i == 2:
        continue
    print(i)

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