写一个fasta id替换代码，其中新id在txt文件 新id内容包含旧id

好的，你可以参考下面的代码实现fasta id替换，其中新id文件中包含旧id和对应的新id。假设fasta文件路径为"E:\泛基因组分析\ORF\ORF_xml\PRRSV.fasta"，新id文件路径为"E:\泛基因组分析\ORF\ORF_xml\PRRSV_newid.txt"：

import os

fasta_file = "E:\泛基因组分析\ORF\ORF_xml\PRRSV.fasta"
new_id_file = "E:\泛基因组分析\ORF\ORF_xml\PRRSV_newid.txt"

if not os.path.exists(fasta_file):
    print("Error: Fasta file does not exist!")
    exit()

if not os.path.exists(new_id_file):
    print("Error: New id file does not exist!")
    exit()

new_ids = {}
try:
    with open(new_id_file, "r", encoding="utf-8") as f:
        for line in f:
            old_id, new_id = line.strip().split()
            new_ids[old_id] = new_id
except:
    print("Error: Failed to read new id file!")
    exit()

try:
    with open(fasta_file, "r", encoding="utf-8") as f:
        lines = f.readlines()
except:
    print("Error: Failed to read fasta file!")
    exit()

new_lines = []
for line in lines:
    if line.startswith(">"):
        # 获取当前id
        old_id = line.strip().lstrip(">")
        # 替换为新id
        if old_id in new_ids:
            new_id = new_ids[old_id]
            new_lines.append(">{}\n".format(new_id))
        else:
            print("Error: Id not found in new id file! ({})".format(old_id))
            exit()
    else:
        new_lines.append(line)

# 将替换后的fasta文件写入新文件
new_fasta_file = "E:\泛基因组分析\ORF\ORF_xml\PRRSV_new.fasta"
with open(new_fasta_file, "w") as f:
    f.writelines(new_lines)

print("Done!")

新id文件中每行包含一个旧id和一个新id，通过读取新id文件构建一个字典new_ids，将旧id作为字典的键，将新id作为字典的值。在处理fasta文件时，如果当前行是id行，则获取当前id，从字典中查找对应的新id并替换。如果当前id在字典中不存在，则输出错误信息并退出程序。最后将替换后的fasta文件写入新文件。