文件操作练习题

import os.path

def read_specific_line(file_path,line_number,encoding="utf-8"):
    if not os.path.exists(file_path):
        return None
    if not isinstance(line_number,int):
        return None

    content  = None
    try:
        fp = open(file_path,"r",encoding=encoding)
        n=1
        for line in fp:
            if n==line_number:
                content = line
                fp.close()
                return content
            n+=1
        fp.close()     
    except:
        print("编码设定错误，请更换编码参数重试！")
        return content

print(read_specific_line("e:\\a.txt",3,"utf-8"))