**While** loop is another type of loops. It performs the same, but the construction of the loop differs.

We use a special variable, i.e. ``counter``, to collect elements of the list. If you want to count the sum of the numbers from 1 to 10 using the while loop, you also have to create a variable that collects and updates the sum after each iteration.

We use `len()` when creating a while loop function to create a suitable iterable.

prices = [100, 458, 231, 378]
i = 0
counter = 0

while i < len(prices):
  counter += prices[i]
  i += 1

print(counter)

# Summing all prices
prices = [3, 5, 6, 2, 7, 8]
i = 0
counter = 0

while i < len(prices):
  counter += prices[i]
  i += 1

print(counter)

When we want to stop our loop immediately, we need to use `break.`

prices = [1, 2, 3, 4, 5, 6]
i = 0

while i < len(prices):
  if prices[i] == 4:
    break
  else:
    print(prices[i])
  i += 1

Introduction to Data Analysis in Python

While Loop