python string not contains code example

Example 1: python string contains substring

fullstring = "StackAbuse"
substring = "tack"

if fullstring.find(substring) != -1:
    print "Found!"
else:
    print "Not found!"

Example 2: python string contains

>>> str = "Messi is the best soccer player"
>>> "soccer" in str
True
>>> "football" in str
False

Example 3: python string does not contain

str = '£35,000 per year'
# check for '£' character in the string
'£' not in str
# >> False
'£' in str
# >> True