读取fasta文件genome_test.fa，并计算染色体总长，同时输出最长染色体编号、序列以及长度

fasta文件genom_test.fa的内容如下：

>chr1

ATATATATAT

>chr2

ATATATATATCGCGCGCGCG

>chr3

ATATATATATCGCGCGCGCGATATATATAT

>chr4

ATATATATATCGCGCGCGCGATATATATATCGCGCGCGCG

>chr5

ATATATATATCGCGCGCGCGATATATATATCGCGCGCGCGATATATATAT

python脚本

1 #传递命令行参数 2 import sys # 导入模块 3  4 # 从命令行获取文件名称 5 f_fasta = sys.argv[1] 6  7 # 打开文件 open('文件路径') 8 f = open(f_fasta) 9 10 # 逐行读取11 total_len = 012 max_chr = ''13 max_seq = ''14 max_len = 015 # 求总长并输出最长染色体编号、序列以及长度16 lines = f.readlines() # 是一个列表17 for line in lines:18     #去掉行尾的换行符19     line = line.strip()20     if (line.startswith(">")):21         chr = line22     else:23         chr_len = len(line)24         chr_seq = line25         max_chr = chr26         max_seq = chr_seq27         max_len = chr_len28         total_len += len(line)29 30 # 输出结果31 print("total_len = " + str(total_len))    32 print("max_chr = " + max_chr)33 print("max_seq = " + max_seq)34 print("max_len = " + str(max_len))

cmd命令行输入

E:\15_python\DEBUG>python fasta_stat6.py genome_test.fa