## Key Concepts

Review core concepts you need to learn to master this subject

### `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
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 …
2. 2
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…
3. 3
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…
4. 4
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…
5. 5
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….
6. 6
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: …