String search and write into a file in jython

I wish to write a program that can read a file and if a particular str_to_find is found in a bigger string, say "AACATGCCACCTGAATTGGATGGAATTCATGCGGGACACGCGGATTACACCTATGAGCAGAAATACGGCCTGCGCGATTACCGTGGCGGTGGACGTTCTTCCGCGCGTGAAACCGCGATGCGCGTAGCGGCAGGGGCGATCGCCAAGAAATACCTGGCGGAAAAGTTCGGCATCGAAATCCGCGGCTGCCTGACCCAGATGGGCGACATTCCGCTGGAGATTAAAGACTGGCGTCAGGTTGAGCTTAATCCGTTTTC"

then write that line and the above line of it into the file and keep repeating it for all the match found.

Please suggest the solution. I have written the program for printing that particular search line but I don't know how to write the above line.

import re
import string
file=open('C:/Users/Administrator/Desktop/input.txt','r')
output=open('C:/Users/Administrator/Desktop/output.txt','w')
count_record=file.readline()
str_to_find='AACCATGC'
while count_record:
 if  string.find(list,str_to_find) ==0:
  output.write(count_record)
file.clos开发者_StackOverflow中文版e()
output.close()

one way

for line in open("file"):
    if "str_to_find" in line:
        print prev
        print line.rstrip()
    prev=line.rstrip()