python将fasta文件均分

step1：将fasta均分为N个文件，每个文件序列数目相等

参考这篇文章：https://blog.csdn.net/whiteof/article/details/123685985

输出结果中每条序列格式均为：id：squence

step2:调整输出fasta格式，将id和sequence分行

import sys

infile, outfile = sys.argv[1], sys.argv[2]

def change_fasta(infa, outfile):

    outf = open(outfile, "w")

    faf = open(infa, "r")

    f = faf.readlines()

    for line in f:

        newline = line.replace(':', '\n')

        outf.write(newline)

change_fasta(infile, outfile)