Python3 File next() Method

Python3 File Methods


Overview

The File object in Python 3 does not support the next() method.

Python 3's built-in next() function calls the __next__() method through an iterator to return the next item. In a loop, the next() method is called each iteration; it returns the next line of the file, and if the end (EOF) is reached, it triggers StopIteration.StopIteration

Syntax

The syntax of the next() method is as follows:

next(iterator[,default])

Parameters

  • None

Return Value

Returns the next line of the file.

Example

The following example demonstrates the usage of the next() method:

The content of the file example.txt is as follows:

This is the first line
This is the second line
This is the third line
This is the fourth line
This is the fifth line

Loop to read the content of the file:

#!/usr/bin/python3

# 打开文件
fo = open("example.txt", "r")
print ("文件名为: ", fo.name)

for index in range(5):
    line = next(fo)
    print ("第 %d 行 - %s" % (index, line))

# 关闭文件
fo.close()

The output of the above example is:

文件名为:  example.txt
第 0 行 - 这是第一行

第 1 行 - 这是第二行

第 2 行 - 这是第三行

第 3 行 - 这是第四行

第 4 行 - 这是第五行


Python3 File Methods

Other Extensions