Unsung Python modules

[Tim Hammerquist]

Skip Montanaro <skip at pobox.com> graced us by uttering:
> 
>     Tim>  1) readline (optional built-in)
>     Tim>  2) xreadlines
> 
>     Tim> Two similarly named but unrelated modules have made my
>     Tim> whole life much easier. =)
> 
> I agree on the readline module (don't have a lot of need to text
> file processing that sys.stdin.readlines() won't handle).

Well, here's the evolution of the textfile iteration:

    # Incarnation 1
    while 1:
        line = fh.readline()
        if not line:
            break
        process(line)
    
    # Incarnation 2
    for line in fh.xreadlines():  # same interface as xreadlines mod
        process(line)
    
    # Incarnation 3 (py2.2+)
    for line in fh:
        process(line)

Python's textfile iteration structures improved by orders of
magnitude with each step.  Sure, sys.stdin.readlines() will do until
I have to parse a daemon log or flat text db; then there's no good
reason or even advantage to loading the whole file in memory at once.

> It seems like I've travelled back to the dark ages whenever I have
> to use Python without readline or a "real" Bourne shell.  Being
> able to recall a line or two from an interactive session from a few
> minutes before (or a few days before) makes day-to-day interaction
> with these tools so much easier.  Readline gets slammed for being a
> bloated pig, but it is a highly useful bloated pig... ;-)

Agreed!  =)

Tim Hammerquist
-- 
Tell me -- How's your love life? Killed any girlfriends
recently?  Or sentenced any more of them to Hell?
    -- Desire to Morpheus, The Sandman