![for Loop
Iterates over a sequence (list, tuple, string, etc.).
Syntax:
for variable in sequence:
# block
Real-Time Example:
cart = ["Shoes", "Shirt", "Watch"]
for item in cart:
print(item)
+-----------+
| Sequence |
+-----------+
↓
+--------+
| Block |
+--------+
↓
Next → End?
Mr. VV, ASP IT](https://image.slidesharecdn.com/pythonprogrammingunitiicontrolstatements-250727064847-f6904343/85/Python-Programming-Unit-II-Control-Statements-ppt-8-320.jpg)
![Nested Loops
A loop inside another loop.
Syntax:
for i in range(n):
for j in range(m):
# block
Real-Time Example:
matrix = [[1,2,3],[4,5,6]]
for row in matrix:
for value in row:
print(value)
Outer Loop → +--------+
| Inner |
+--------+
↓
+--------+
| Block |
+--------+
Mr. VV, ASP IT](https://image.slidesharecdn.com/pythonprogrammingunitiicontrolstatements-250727064847-f6904343/85/Python-Programming-Unit-II-Control-Statements-ppt-10-320.jpg)
![break Statement
Exits the loop prematurely when condition is met.
Syntax:
for variable in sequence:
if condition:
break
Real-Time Example:
for num in [1,2,0,3]:
if num == 0:
break
print(num)
+-----------+
| Condition |
+-----------+
Yes → Exit Loop
No → Continue
Mr. VV, ASP IT](https://image.slidesharecdn.com/pythonprogrammingunitiicontrolstatements-250727064847-f6904343/85/Python-Programming-Unit-II-Control-Statements-ppt-11-320.jpg)
![continue Statement
Skips current iteration and continues with next.
Syntax:
for variable in sequence:
if condition:
continue
Real-Time Example:
for num in [-2,-1,0,1,2]:
if num < 0:
continue
print(num)
+-----------+
| Condition |
+-----------+
Yes → Skip Current Iteration
No → Normal Flow
Mr. VV, ASP IT](https://image.slidesharecdn.com/pythonprogrammingunitiicontrolstatements-250727064847-f6904343/85/Python-Programming-Unit-II-Control-Statements-ppt-12-320.jpg)
![ Iteration (Loops)
while loop → Runs until condition false
Example: while stock>0: stock-=1
for loop → Iterates over sequence
Example: for item in cart: print(item)
else in loop → Runs if no break
Example: for n in range(3): print(n) else: print("Done")
nested loops → Loop inside loop
Example: for r in matrix: for v in r: print(v)
Mr. VV, ASP IT
Selection (Branching)
if → Executes only if condition true
Example: if temp > 30: print("Hot day")
if-else → Executes one block else another
Example: if age>=18: print("Vote") else: print("No")
if-elif-else → Multiple conditions
Example: if marks>=90: ... elif marks>=75: ... else: ...
nested if → if inside if
Example: if logged: if admin: print("Admin")
Jump Statements
break → Exit loop early
Example: for n in [1,2,0,3]: if n==0: break
continue → Skip iteration
Example: for n in [-2,-1,1]: if n<0: continue; print(n)
pass → Placeholder, does nothing
Example: def future(): pass](https://image.slidesharecdn.com/pythonprogrammingunitiicontrolstatements-250727064847-f6904343/85/Python-Programming-Unit-II-Control-Statements-ppt-14-320.jpg)
Python Programming Unit II Control Statements.ppt
- 1. PYTHON PROGRAMMING VEERANAN VEERANAN Assistant Professor in Information Technology P.K.N. Arts and Science College Tirumangalam Madurai.
- 2. Python Control Statements ⬇ Selection ├─ if ├─ if-else ├─ if-elif-else └─ nested if ⬇ Iteration ├─ while │ └─ else-with-loop └─ for └─ nested loops ⬇ Jump Statements ├─ break ├─ continue └─ pass Mr. VV, ASP IT Overview
- 3. if Statement Executes a block of code only if the condition is true. Syntax if condition: # code block Real-Time Example: temperature = 35 if temperature > 30: print("It's a hot day") +-----------+ | Condition | +-----------+ Yes | No ↓ ↓ +--------+ (Skip) | Block | +--------+ Mr. VV, ASP IT
- 4. if-else Statement Executes one block if the condition is true, otherwise executes another. Syntax: if condition: # code block if true else: # code block if false Real-Time Example: age = 17 if age >= 18: print("Eligible to vote") else: print("Not eligible to vote") +-----------+ | Condition | +-----------+ Yes | No ↓ ↓ +--------+ +--------+ | Block1 | | Block2 | +--------+ +--------+ Mr. VV, ASP IT
- 5. Nested if Statement An if statement inside another if statement. Syntax: if condition1: if condition2: # block Real-Time Example: is_logged_in = True is_admin = True if is_logged_in: if is_admin: print("Welcome Admin!") +-----------+ | Cond1 | +-----------+ Yes | No ↓ ↓ +-----------+ (Skip) | Cond2 | +-----------+ Yes | No ↓ ↓ +--------+ (Skip) | Block | +--------+ Mr. VV, ASP IT
- 6. if-elif-else Statement Checks multiple conditions one by one until one is true. Syntax: if condition1: # block1 elif condition2: # block2 else: # block3 Real-Time Example: marks = 82 if marks >= 90: print("Grade A") elif marks >= 75: print("Grade B") else: print("Grade C") +-----------+ → Yes → +--------+ | Cond1 | | Block1 | +-----------+ +--------+ No ↓ +-----------+ → Yes → +--------+ | Cond2 | | Block2 | +-----------+ +--------+ No ↓ +-----------+ | Default | +-----------+ Mr. VV, ASP IT
- 7. while Loop Repeats a block of code while the condition is true. Syntax: while condition: # block Real-Time Example: stock = 5 while stock > 0: print("Selling item") stock -= 1 +-----------+ | Condition | +-----------+ Yes | No ↓ ↓ +--------+ Exit | Block | +--------+ ↑ +-- Repeat Mr. VV, ASP IT
- 8. for Loop Iterates over a sequence (list, tuple, string, etc.). Syntax: for variable in sequence: # block Real-Time Example: cart = ["Shoes", "Shirt", "Watch"] for item in cart: print(item) +-----------+ | Sequence | +-----------+ ↓ +--------+ | Block | +--------+ ↓ Next → End? Mr. VV, ASP IT
- 9. else with Loop Executes else block if loop completes normally (no break). Syntax: for variable in sequence: # loop block else: # block executed after loop Real-Time Example: for n in range(3): print(n) else: print("Loop Finished") Loop Completed (no break)? ↓ +--------+ | else | +--------+ Mr. VV, ASP IT
- 10. Nested Loops A loop inside another loop. Syntax: for i in range(n): for j in range(m): # block Real-Time Example: matrix = [[1,2,3],[4,5,6]] for row in matrix: for value in row: print(value) Outer Loop → +--------+ | Inner | +--------+ ↓ +--------+ | Block | +--------+ Mr. VV, ASP IT
- 11. break Statement Exits the loop prematurely when condition is met. Syntax: for variable in sequence: if condition: break Real-Time Example: for num in [1,2,0,3]: if num == 0: break print(num) +-----------+ | Condition | +-----------+ Yes → Exit Loop No → Continue Mr. VV, ASP IT
- 12. continue Statement Skips current iteration and continues with next. Syntax: for variable in sequence: if condition: continue Real-Time Example: for num in [-2,-1,0,1,2]: if num < 0: continue print(num) +-----------+ | Condition | +-----------+ Yes → Skip Current Iteration No → Normal Flow Mr. VV, ASP IT
- 13. pass Statement Definition: Placeholder for future code, does nothing. Syntax: if condition: pass Real-Time Example: def future_function(): pass # TODO: implement later +-----------+ | pass | +-----------+ (No action) Mr. VV, ASP IT
- 14. Iteration (Loops) while loop → Runs until condition false Example: while stock>0: stock-=1 for loop → Iterates over sequence Example: for item in cart: print(item) else in loop → Runs if no break Example: for n in range(3): print(n) else: print("Done") nested loops → Loop inside loop Example: for r in matrix: for v in r: print(v) Mr. VV, ASP IT Selection (Branching) if → Executes only if condition true Example: if temp > 30: print("Hot day") if-else → Executes one block else another Example: if age>=18: print("Vote") else: print("No") if-elif-else → Multiple conditions Example: if marks>=90: ... elif marks>=75: ... else: ... nested if → if inside if Example: if logged: if admin: print("Admin") Jump Statements break → Exit loop early Example: for n in [1,2,0,3]: if n==0: break continue → Skip iteration Example: for n in [-2,-1,1]: if n<0: continue; print(n) pass → Placeholder, does nothing Example: def future(): pass