File seek( ) Method in Python 3
The method seek() sets the file's current
position at the offset. The whence argument is optional and defaults to 0,
which means absolute file positioning, other values are 1 which means seek
relative to the current position and 2 means seek relative to the file's end.There
is no return value. Note that if the file is opened for appending using either
'a' or 'a+', any seek() operations will be undone at the next write.
If the file is only opened for writing in append mode
using 'a', this method is essentially a no-op, but it remains useful for files
opened in append mode with reading enabled (mode 'a+').
If the file is opened in text mode using 't', only
offsets returned by tell() are legal. Use of other offsets causes undefined behavior.
Note that not all file objects are seekable.
Syntax
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fileObject.seek(offset[,
whence])
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Parameters
- offset- This is the position of the read/write pointer within the file.
- whence- This is optional and defaults to 0 which means absolute file positioning,other values are 1 which means seek relative to the current position and 2 means seek relative to the file's end.
Return Value
This method does not return any value.
Example
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Assuming
that 'foo.txt' file contains following text:
This is
1st line
This is
2nd line
This is
3rd line
This is
4th line
This is
5th line
|
|
#!/usr/bin/python3
# Open
a file
fo =
open("foo.txt", "rw+")
print
("Name of the file: ", fo.name)
line =
fo.readlines()
print
("Read Line: %s" % (line))
# Again
set the pointer to the beginning
fo.seek(0,
0)
line =
fo.readline()
print
("Read Line: %s" % (line))
# Close
opened file
fo.close()
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When we run the above program, it produces the
following result
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Name of
the file: foo.txt
Read
Line: ['This is 1st line\n', 'This is
2nd line\n',
'This is 3rd line\n','This is 4th line\n', 'This is
5th line']
Read
Line: This is 1st line
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