For loop

Definition

A for loop is a control flow statement that iterates over a sequence (such as a list, tuple, or string) and executes a block of code for each item in the sequence. It is commonly used to repeat actions a specific number of times or to traverse data structures.

5 Must Know Facts For Your Next Test

1. A for loop uses the syntax: 'for item in sequence:' followed by an indented block of code.
2. The range() function is often used with for loops to generate sequences of numbers.
3. For loops can be nested inside other loops to handle multi-dimensional data structures.
4. The break statement can be used within a for loop to exit it prematurely.
5. For loops can iterate over any iterable object, including lists, tuples, strings, and dictionaries.

Review Questions

• What is the primary purpose of a for loop?
• How would you create a for loop that iterates over the numbers 0 to 9?
• What keyword would you use to exit a for loop before it finishes all its iterations?

Related terms

while loop:

A control flow statement that repeatedly executes a block of code as long as its condition remains true.

range():

A built-in function used with for loops to generate sequences of numbers.

break:

A statement used within loops to exit the current iteration and terminate the loop.