python if string does not contain code example

Example 1: if substring not in string python

fullstring = "StackAbuse"
substring = "tack"

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

Example 2: python check if string in string

if "blah" not in somestring: 
    continue

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