Control structures are essential for making decisions and executing code conditionally. In this post, we will explore Python’s control structures, including conditional statements and loops.
1. Conditional Statements
Conditional statements allow you to execute different blocks of code based on certain conditions.
1.1. if Statement
The if statement executes a block of code if a specified condition is true.
Syntax:
python
if condition:
# block of code
Example:
python
age = 18
if age >= 18:
print("You are an adult.")
Output:
sql
You are an adult.
1.2. if-else Statement
The if-else statement executes one block of code if a condition is true and another block of code if the condition is false.
Syntax:
python
if condition:
# block of code if condition is true
else:
# block of code if condition is false
Example:
python
age = 16
if age >= 18:
print("You are an adult.")
else:
print("You are a minor.")
Output:
css
You are a minor.
1.3. if-elif-else Statement
The if-elif-else statement allows you to check multiple conditions.
Syntax:
python
if condition1:
# block of code if condition1 is true
elif condition2:
# block of code if condition2 is true
else:
# block of code if none of the conditions are true
Example:
python
marks = 85
if marks >= 90:
print("Grade: A")
elif marks >= 75:
print("Grade: B")
elif marks >= 50:
print("Grade: C")
else:
print("Grade: F")
Output:
makefile
Grade: B
2. Loops
Loops are used to execute a block of code repeatedly as long as a certain condition is met.
2.1. for Loop
The for loop is used to iterate over a sequence (such as a list, tuple, string) or other iterable objects.
Syntax:
python
for item in sequence:
# block of code
Example:
python
# Iterating over a list
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
print(fruit)
Output:
apple
banana
cherry
2.2. while Loop
The while loop executes a block of code as long as a specified condition is true.
Syntax:
python
while condition:
# block of code
Example:
python
count = 1
while count <= 5:
print(count)
count += 1
Output:
1
2
3
4
5
2.3. break, continue, and pass Statements
- break: Terminates the loop prematurely.
- continue: Skips the rest of the code inside the loop for the current iteration and moves to the next iteration.
- pass: Does nothing; acts as a placeholder.
Example:
python
# Using break
for i in range(10):
if i == 5:
break
print(i)
# Using continue
for i in range(10):
if i % 2 == 0:
continue
print(i)
# Using pass
for i in range(5):
if i == 3:
pass
print(i)
Output:
0
1
2
3
4
1
3
5
7
9
0
1
2
3
4
Conclusion
In this post, we covered Python’s control structures, including conditional statements and loops. These constructs are essential for controlling the flow of your programs. In the next post, we will explore functions in Python, how to define and use them, and the difference between built-in and user-defined functions. Stay tuned!
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