seeking thru a file

[Mag Gam]

I have a compressed CSV gziped file. I was wondering if it is possible
to seek thru a file

For example:

I want to load the first 100 lines into an array. Process the data

Seek from 101 line to 200 lines. Process the data (remove lines 0 -
100) from memory

Seek 201 to 300 line. Process the data (remove 200-300)) from memory

etc..etc..