Key Concepts

Review core concepts you need to learn to master this subject

break Keyword

Python List Comprehension

Python For Loop

The Python continue Keyword

Python Loops with range().

Infinite Loop

Python while Loops

Python Nested Loops

break Keyword

numbers = [0, 254, 2, -1, 3]

for num in numbers:
  if (num < 0):
    print("Negative number detected!")
    break
  print(num)
  
# 0
# 254
# 2
# Negative number detected!

In a loop, the break keyword escapes the loop, regardless of the iteration number. Once break executes, the program will continue to execute after the loop.

In this example, the output would be:

  • 0
  • 254
  • 2
  • Negative number detected!
Loops
Lesson 1 of 2
  1. 1
    Introduction to Loops
    How do we use code to tell a computer this: “Create a variable and call a function 15 times”? We could write it out 15 times: create a variable call a function create a variable call a function …
    Start
  2. 2
    For Loops
    When we give instructions once and tell the computer how many times to repeat them, we are using a for loop, or a count-controlled loop. It executes a set of instructions for a specified numb…
    Start
  3. 3
    While Loops
    What if you approached tile-placing another way: you don’t know how many tiles to place, but you know when to stop. How could you communicate this type of command to a computer? Give it the instruc…
    Start
  4. 4
    For Each Loops
    There’s one more way to give looping instructions to a computer. We define a sequence of desired tile colors (a list), and tell the computer to repeat the instructions for each item in the sequen…
    Start
  5. 5
    Putting it All Together
    Let’s combine all that we’ve learned so far: * variables, operators, and data types * functions and control flow * lists and loops Examples of for and while loops are provided below in JavaScript….
    Start
  6. 6
    Review
    Well done! Loops are commonly used in programming because they save time, reduce error, and are easy to read. Being comfortable with each type of loop will make you a better programmer. In review: …
    Start