We often want to use a for loop to search through a list for some value:
items_on_sale = ["blue_shirt", "striped_socks", "knit_dress", "red_headband", "dinosaur_onesie"] # we want to check if the item with ID "knit_dress" is on sale: for item in items_on_sale: if item == "knit_dress": print("Knit Dress is on sale!")
This code goes through each
items_on_sale and checks for a match. After we find that
"knit_dress" is in the list
items_on_sale, we don’t need to go through the rest of the
items_on_sale list. Since it’s only 5 elements long, iterating through the entire list is not a big deal in this case. But what if
items_on_sale had 1000 items after
"knit_dress"? What if it had 100,000 items after
You can stop a for loop from inside the loop by using
break. When the program hits a
break statement, control returns to the code outside of the for loop. For example:
items_on_sale = ["blue_shirt", "striped_socks", "knit_dress", "red_headband", "dinosaur_onesie"] print("Checking the sale list!") for item in items_on_sale: print(item) if item == "knit_dress": break print("End of search!")
This would produce the output:
Checking the sale list! blue_shirt striped_socks knit_dress End of search!
We didn’t need to check
"dinosaur_onesie" at all!
You have a list of dog breeds you can adopt,
dog_breeds_available_for_adoption. Using a for loop, iterate through the
dog_breeds_available_for_adoption list and print out each dog breed.
Inside your for loop, after you print each dog breed, check if it is equal to
dog_breed_I_want. If so, print
"They have the dog I want!"
Add a break statement when your loop has found
dog_breed_I_want, so that the rest of the list does not need to be checked.