ROSALIND - Locating Restriction Sites solution to https://rosalind.info/problems/revp/

 c_map = {  
   "A":"T",  
   "G":"C",  
   "C":"G",  
   "T":"A"  
 }  
 def GetComplement(seq):  
   r = ''.join([c_map[x] for x in seq])  
   return r  
 def GetRevComplement(seq):  
   c = GetComplement(seq)   
   return c[::-1]    
 f = open("out.txt", "w")  
 input_file = open("rosalind_revp.txt", "r")  
 seq = ""  
 lines = input_file.readlines()  
 for l in lines:  
   if (l[0]!=">"):  
     seq = seq + l.replace("\n", "").replace("\r","")  
 seq_len = len(seq)  
 start_len = 2  
 end_len = 6  
 found_list = {}  
 for i in range(start_len, end_len+1):   
   for j in range(0, seq_len-(i*2)+1):  
     first_half = seq[j:j+i]  
     second_half =seq[j+i:j+i*2]  
     rc_second_half = GetRevComplement(second_half)  
     if (first_half == rc_second_half):  
       #print(first_half + " " + second_half + " " + rc_second_half + " " + str(j+1) + " " +str(i*2))  
       found_list[j+1]=i*2  
 sorted_found_list = sorted(found_list.items(), key=lambda item: item[0])  
 for key, value in sorted_found_list:  
   print(str(key) + " " + str(value))        
   f.write(str(key) + " " + str(value) + '\n')  
 f.close()