reversing string in python

[python101]

How can I print the output out(the mutated DNA)? I got error message.

How can I make the program run without being interrupted (after input the dna and pat, it outputs the result, then it appears the input again,...) when I want it to stop I type 'exit' and 'quit' to make it stop running?

[bartonc]

How can I print the output out(the mutated DNA)? I got error message.

How can I make the program run without being interrupted (after input the dna and pat, it outputs the result, then it appears the input again,...) when I want it to stop I type 'exit' and 'quit' to make it stop running?

[CODE=python]# Use lots of comments
# to describe your program

# put imports at the top
import sys

def CheckDNASequenc e(sequence):
# just a stub
return True


# "encapsulat e" using functions
def GetDNASequence( ): # use descriptive names
while 1: # alway loop
seq = raw_input("Ente r a sequence ('q' to quit): ")
if seq.lower() == "q":
return # break out of the loop, returning None
if CheckDNASequenc e(seq): # break out of the loop
break
return seq # good practice to put the valid return here

def GetPattern():
pat = raw_input("Ente r a pattern: ")
return pat


def main():
while True: # always loop
seq = GetDNASequence( )
if seq is None:
sys.exit()
print seq
pat = GetPattern()
print pat

if __name__ == "__main__":
main()[/CODE]