python课后作业1

</pre><pre name="code" class="python">from __future__ import divisionfasta_file =open('D:/learningsources/python/managepython/5-seq.fa.txt','r+')out_file =open('D:/learningsources/python/managepython/frq.txt','w+')AA_dic = {}.fromkeys(['A','R','D','C','Q','E','H','I','G','N','L','K','M','F','P','S','T','W','Y','V'],0)AA = 'ARDCQEHIGNLKMFPSTWYV'seq=''AC=''for line in fasta_file:    if line[0] =='>' and seq =='':        AC=line        out_file.write(AC)    elif line[0] !='>' and seq == '':        seq=line        L=len(seq)        for a in AA:            AA_dic[a] = seq.count(a)             for k,v in AA_dic.items():            out_file.write("%s %s %5.4f " % (k,':',v/L)+'\t')        out_file.write('\n')        seq=''           out_file.close()