在Python中使用next()方法操作文件的教程

next()方法当一个文件被用作迭代器，典型例子是在一个循环中被使用，next()方法被反复调用。此方法返回下一个输入行，或引发StopIteration异常EOF时被命中。

与其它文件的方法，如ReadLine()相结合next()方法工作不正常。然而，usingseek()将文件重新定位到一个绝对位置将刷新预读缓冲器。
语法

以下是next()方法的语法：

    fileObject.next(); 

参数

• NA

返回值

此方法返回下一个输入行。
例子

下面的示例演示next()方法的使用。

    #!/usr/bin/python

    # Open a file
    fo = open("foo.txt", "rw+")
    print "Name of the file: ", fo.name

    # Assuming file has following 5 lines
    # This is 1st line
    # This is 2nd line
    # This is 3rd line
    # This is 4th line
    # This is 5th line

    for index in range(5):
      line = fo.next()
      print "Line No %d - %s" % (index, line)

    # Close opend file
    fo.close()

当我们运行上面的程序，它会产生以下结果：

    Name of the file: foo.txt
    Line No 0 - This is 1st line

    Line No 1 - This is 2nd line

    Line No 2 - This is 3rd line

    Line No 3 - This is 4th line

    Line No 4 - This is 5th line