1 """ReverseComplement using BioPython
   2 """
   3 
   4 import sys
   5 from Bio import Fasta
   6 
   7 dictDnaComp = {'A':'T', 'T':'A', 'G':'C', 'C':'G'}
   8 
   9 def main(infilename, outfilename):
  10     try:
  11         infile = open(infilename, 'r')
  12         outfile = open(outfilename, 'w')
  13     except:
  14         print "Error: unable to open file"
  15         sys.exit()
  16     parser = Fasta.RecordParser()
  17     iterator = Fasta.Iterator(infile, parser)
  18     while 1:
  19         curRecord = iterator.next()
  20         if curRecord is None: break
  21         curRecord.sequence = convert(curRecord.sequence)
  22         outfile.write(str(curRecord))
  23 
  24 def convert(aSeq):
  25     newSeq = ''
  26     for index in range(len(aSeq)-1, -1, -1):
  27         newSeq += dictDnaComp[aSeq[index]]
  28     return newSeq
  29 
  30 if __name__ == '__main__': 
  31     ifile, ofile = sys.argv[1:3]
  32     main(ifile, ofile)