Python break

Question

Released is a dict
For i in released:
If "s" in released:
Print(yes)
Break
Else:
Print(not found)

Why to use break here

Answer 1

When you loop through a dictionary like this, the variable i will become one of the dict keys (in non-determined order).
So it does not make sense to iterate again through all dictionary elements in the next line, you should just write:
if i == "s":

Also an easy way to check if a key exists in a dictionary:

d = {1: 'one', 2: 'two'}
print(1 in d) # True
print(3 in d) # False

Answer 2

Here, this code checks if "s" is in the list. If it is matched once, you know that "s" is in the list, so you don't need to go further and you can escape the loop using keyword break.

Imagine the list is containing one billion of elements, and "s" can be matched at index 3. Do you really need to go further and check all elements in the list? It's a waste of time, so break the loop.