Control Flow: Guiding the Execution Path

Control flow dictates the order in which instructions are executed within a program. Python offers constructs like conditional statements and loops to manage this flow.

1. Conditional Statements: Making Decisions

  • if-elif-else Statement: Allows your program to branch execution based on conditions.
graph LR
    A[Start] --> B{Condition 1 True?}
    B -- Yes --> C[Execute Block 1]
    B -- No --> D{Condition 2 True?}
    D -- Yes --> E[Execute Block 2]
    D -- No --> F[Execute 'else' Block]
    C --> G[End]
    E --> G
    F --> G

1x = 10
2
3if x > 15:
4    print("x is greater than 15")
5elif x > 5:
6    print("x is greater than 5 but not greater than 15")
7else:
8    print("x is less than or equal to 5")

2. Loops: Repeating Code Blocks

  • for Loop: Iterates over a sequence (like a list or string).
graph LR
    A[Start] --> B{For each item in sequence}
    B -- Yes --> C[Execute Loop Body]
    C --> B
    B -- No --> D[End] 

1fruits = ["apple", "banana", "cherry"]
2for fruit in fruits:
3    print(fruit)
  • while Loop: Repeats a block of code as long as a condition holds true.
graph LR
    A[Start] --> B{Condition True?}
    B -- Yes --> C[Execute Loop Body]
    C --> B
    B -- No --> D[End] 

1count = 0 
2while count < 5:
3    print(count)
4    count += 1

3. break and continue Statements: Modifying Loop Behavior

  • break: Exits the loop prematurely.

  • continue: Skips the current iteration and jumps to the next.

Notes: if-elif-else lets you make decisions, while for and while loops automate repetitive tasks.

Read: Python Built-In Functions