Read specific bytes of file in python

python seek
user3124171 picture user3124171 · Mar 31, 2015 · Viewed 26k times · Source

I want to specify an offset and then read the bytes of a file like 

offset = 5
read(5)

and then read the next 6-10 etc. I read about seek but I cannot understand how it works and the examples arent descriptive enough.

seek(offset,1) returns what?

Thanks

Answer

Santa picture Santa · Mar 31, 2015

Just play with Python's REPL to see for yourself:

[...]:/tmp$ cat hello.txt 
hello world
[...]:/tmp$ python
Python 2.7.6 (default, Mar 22 2014, 22:59:56) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> f = open('hello.txt', 'rb')
>>> f.seek(6, 1)    # move the file pointer forward 6 bytes (i.e. to the 'w')
>>> f.read()        # read the rest of the file from the current file pointer
'world\n'

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