if "blah" not in somestring:
continue
s1 = 'perpendicular'
s2 = 'pen'
s3 = 'pep'
print(''pen' in 'perpendicular' -> {}'.format(s2 in s1))
print(''pep' in 'perpendicular' -> {}'.format(s3 in s1))
# Output
# 'pen' in 'perpendicular' -> True
# 'pep' in 'perpendicular' -> False
# If you are more interested in finding the location of a substring within a string
# (as opposed to simply checking whether or not the substring is contained),
# the find() string method can be more helpful.
s = 'Does this string contain a substring?'
print(''string' location -> {}'.format(s.find('string')))
print(''spring' location -> {}'.format(s.find('spring')))
# Output
# 'string' location -> 10
# 'spring' location -> -1
# find() returns the index of the first character of the first occurrence of the substring by default,
# and returns -1 if the substring is not found