用python把文件内容按照染色体编号写出（第十一题）

测试文件见我的github.

import os
os.chdir('G:/R/Genome/hsa')
def readfasta(filename):
    """
    :param filename: ；要读取的FASTA文件名
    :return: 返回基因名：序列的字典文件
    """

    fa = open(filename, 'r')
    res = {}
    ID = ''
    for line in fa:
        if line.startswith('>'):
            ID = line.strip('\n')[1:]
            res[ID] = ''
        else:
            res[ID] += line.strip('\n')

    return res

def seperatefile(filename, outfile):
    data=readfasta(filename)
    for key, value in data.items():
        (file, ext)=os.path.splitext(outfile)
        fo=open('%s_%s%s' % (file, key, ext), 'w')
        fo.write('>%s\n'%key)
        fo.write('%s\n'%value)
seperatefile('genome.fa', 'output.fa')