i am facing some problem with files with huge data.
i need to skip doing some execution on those files.
i get the data of the file into a variable.
now i need to get the byte of the variable and if it is greater than 102400 , then print a message.
update : i cannot open the files , since it is present in a tar file. 
         the content is already getting copied to a variable called 'data'
         i am able to print contents of the variable data. i just need to check if it has more than 102400 bytes.
thanks
This answer seems irrelevant, since I seem to have misunderstood the question, which has now been clarified. However, should someone find this question, while searching with pretty much the same terms, this answer may still be relevant:
Just open the file in binary mode
f = open(filename, 'rb')
read/skip a bunch and print the next byte(s). I used the same method to 'fix' the n-th byte in a zillion images once.
how do i get the byte count of a variable in python just like wc -c gives in unix