Question

in python, file.readlines() get all line, it’s waste if file size is large(several Mb). is there a efficient way to get parts of files as page?
usually the part text display as a page in webapp, consider text are to be further decorated.

Answer 1

currently i though of a rough way by byte size:

import os
def getpage(fname, pageindex, pagesize=100, ahead=20):
    """read page roughly by byte size"""
    size = os.path.getsize(fname)
    pagenum = size/pagesize
    f=open(fname,'r')
    pos=pageindex * pagesize
    #ahead some line
    pos -= ahead
    if pos <0: 
        pos = 0
    f.seek(pos)
    f.readline()
    txt = f.read(pagesize)
    txt += f.readline()    
    return txt

it’s not fixed lines, some text are loose, some tight. but for moderate pagesize, it’s ok for user’s view.