代码如下:
import os ## for os.path.isfile()
def dealline(line) :
    print(line) ## 针对line我可以做很多事情
def getfilename() :
    return input('please input file name(input exit() for exit):').strip()
class more : ## more功能
    linenum = 0
    size = 10
    def work(self) :
        if self.linenum >= self.size :
            if input('--more--').strip().lower() == 'exit()' :
                return false
            self.linenum = 0
        else :
            self.linenum += 1
        return true
while true :
    try :
        filename = getfilename()
        if filename.lower() == 'exit()' : ## 退出
            break
        if os.path.isfile(filename) : ## 判断文件是否存在
            f = open(filename)
            try :
                lines = f.readlines()
                m = more()
                for line in lines:
                    if false == m.work() :
                        break
                    dealline(line)
## input()
            finally :
                f.close()
        else :
            print('file does not exists.')
            ##input()
    except :
        print('input error!')
还可以用
代码如下:
with open(filename) as fh:
    for line in fh:
        yield line
输出每一行