The `in` and `not in` operators¶

The in operator tests if one string is a substring of another:

print('p' in 'apple')
print('i' in 'apple')
print('ap' in 'apple')
print('pa' in 'apple')

(chp8_in1)

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!)

print('a' in 'a')
print('apple' in 'apple')
print('' in 'a')
print('' in 'apple')

(chp8_in2)

The not in operator returns the logical opposite result of in.

print('x' not in 'apple')

(chp8_in3)

The in and not in operators¶

The `in` and `not in` operators¶