s="指定字符串"f=open("文本文件名")n=int(raw_input("输入输出的行数:"))line=f.readline()while line:   if s in line:   print line   for i in range(n):   line=f.readline()   if line:   print line   else:   break   if not line:break   line=f.readline()    
python 如何在文本中找到某个单词的所在行并在后面添加两行内容?急求
    s="指定字符串"f=open("文本文件名")n=int(raw_input("输入输出的行数:"))line=f.readline()while line:    if s in line:        print line        for i in range(n):            line=f.readline()            if line:                print line            else:                break        if not line:break    line=f.readline()2018-11-04