not in operators¶
in operator tests if one string is a substring of another:
Note that a string is a substring of itself, and the empty string is a substring of any other string. (Also note that computer scientists like to think about these edge cases quite carefully!)
not in operator returns the logical opposite result of
We can also use the
not in operators on lists!
However, remember how you were able to check to see if an “a” was in “apple”? Let’s try that again to see if there’s an “a” somewhere in the following list.
Clearly, we can tell that a is in the word apple, and absolutely, and application. For some reason
though, the Python interpreter returns False. Why is that? When we use the
operators on lists, Python checks to see if the item on the left side of the expression is equivalent
to an element in the item on the right side of the expression. In this case, Python is checking
whether or not an element of the list is the string “a” - nothing more or less than that.