Python File Next() Method

Description

Python file method next() is used when a file is used as an iterator, typically in a loop, the next() method is called repeatedly. This method returns the next input line or raises StopIteration when EOF is hit.

Combining next() method with other file methods like readline() does not work right. However, usingseek() to reposition the file to an absolute position will flush the read-ahead buffer.

Syntax

Following is the syntax for next() method:

fileObject.next();  

Parameters

• NA

Return Value

This method returns the next input line.

Example

The following example shows the usage of next() method.

This is 1st line
This is 2nd line
This is 3rd line
This is 4th line
This is 5th line

#!/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()

When we run the above program, it produces the following result:

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

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