Python 从第几行开始读取文件

lines = []
with codecs.open("./luanxu.txt", 'r', 'gb18030') as infile:
    for i in infile.readlines()[25701:30519]:
        lines.append(i)

#将读取数据保存新文件中
with codecs.open("./cnews.test.txt", 'w','gb18030') as f:
    for line in lines:
        f.write(line)

从文件的第25701行开始读数据，读到第30519行