Python loops

Loops are a fundamental concept in programming that allow you to repeat a block of code multiple times. Python supports two main types of loops: "for" loops and "while" loops. These loops are used to automate repetitive tasks and iterate through collections of data. Here's an introduction to both types of loops:

  • For Loops:

    • A "for" loop is used to iterate over a sequence (like a list, tuple, string, or range) and execute a block of code for each item in the sequence.

    fruits = ['apple', 'banana', 'orange']

for fruit in fruits:
    print(fruit)

    In this example, the "for" loop iterates over each item in the "fruits" list and prints each fruit name.

    You can also use the range() function to generate a sequence of numbers to iterate over:

    for num in range(1, 6):
    print(num)

    This loop will print the numbers 1 to 5.

  • While Loops:

    • A "while" loop repeatedly executes a block of code as long as a specified condition is true.

    count = 0

while count < 5:
    print(count)
    count += 1

    In this example, the "while" loop will keep printing the value of "count" as long as it's less than 5. The loop will terminate when the condition becomes false.

  • Loop Control Statements:

    • Both "for" and "while" loops can be controlled using certain statements:

    • break: Terminates the loop prematurely.
    • continue: Skips the rest of the current iteration and moves to the next iteration.
    • else (for "for" loops): Executes a block of code when the loop completes normally (i.e., not interrupted by a "break").
  • Infinite Loops:

    • Be careful with loops to avoid creating infinite loops—loops that never stop. Make sure that your loop's condition can eventually become false, or use techniques like incrementing a counter or breaking the loop explicitly.

  • Choosing Between For and While:
    • Use a "for" loop when you know the number of iterations beforehand (e.g., iterating through a list).
    • Use a "while" loop when you're unsure about the number of iterations or need to repeatedly execute code until a certain condition is met.

Loops are vital tools for automating repetitive tasks, iterating through data, and controlling the flow of your program based on conditions.