python-删除文件的特定行

def removeLine(filename, lineno):
    fro = open(filename, "r",encoding='UTF-8')

    current_line = 0
    while current_line < lineno:
        fro.readline()
        current_line += 1

    seekpoint = fro.tell()
    frw = open(filename, "r+")
    frw.seek(seekpoint, 0)

    # read the line we want to discard
    fro.readline()  # 读入一行进内存 ，同时 文件指针下移实现删除

    # now move the rest of the lines in the file
    # one line back
    chars = fro.readline()
    while chars:
        frw.writelines(chars)
        chars = fro.readline()

    fro.close()
    frw.truncate()
    frw.close()