text: from Bio import SeqIO
  from Bio.Seq import Seq, reverse_complement, transcribe, back_transcribe, translate
  import re
  import time
  
  A_t = 0;
  G_t = 0;
  C_t = 0;
  T_t = 0;
  All = 0;
  All_r = 0;
  
  '''
  x1 = open("test.fna")
  for seq in SeqIO.parse(x1,'fasta'):
      All_r+=1;
      for word in seq:
          All+=1;
          if word=='A':
              A_t+=1;
          elif word=='C':
              C_t+=1;
          elif word=='G':
              G_t+=1;
          elif word=='T':
              T_t+=1;
  
  print 'A_t->',A_t,'G_t->',G_t,'C_t->',C_t,'T_t->',T_t;
  print 'ALL->',All;
  print 'average length->', All//All_r;
  '''
  signal = 0;
  New_string = '';
  x1 = open("10xtest_GC44.fasta")
  for seq in SeqIO.parse(x1,'fasta'):
      if signal == 0:
         New_string+='>'
         New_string+=seq.id;
         New_string+='\n'
         New_string+=seq.seq.tostring();
         New_string+='\n';
         signal = 1;
      elif signal == 1:
          signal = 0;
          
  x2 = open("single.fasta",'w')
  x2.write(New_string)
  x2.close()
  