[Tutor] Clear screen questions

[Brian van den Broek]

On 5 May 2013 23:12, Steven D'Aprano <steve at pearwood.info> wrote:
>
> On 06/05/13 12:37, Brian van den Broek wrote:

<snip>

>> Try:
>>
>> def pragmatic_as_if_clear():
>>      print '\n' * 100
>>
>> which isn't too far off of what clear does in bash.
>
> Not in the version of bash I am using in an xterm window. (To be precise,
> Konsole under KDE 3.)
>
> If I start a bash session, and then do something "large" like print a file
> listing, the prompt ends up right at the bottom of the screen. If I then
> call clear, the visible area of the screen is cleared, the prompt ends up at
> the top of the screen, but if I scroll back using the scroll bar, I can see
> the previous output immediately before the clear command, without 100 blank
> lines separating them.


terminator 0.93 under openbox 3.5 appears to fill a terminal window
height with blank lines. That isn't a hard coded value as above, but
that's why I put in the weasel words. Since those words are there,
I'll press them into service to cover the further inaccuracy you point
out :-)


>>>>> A second question is that one person had as the answer to use:
>>>>>
>>>>> os.system( [ 'clear', 'cls' ][ os.name == 'nt' ] )
>>>>>
>>>>> I don't understand this syntax. The writer said that if one
>>>>> understands what this is doing, then the method is more generally
>>>>> useful. Would someone explain how this works? And hopefully it will
>>>>> become apparent to me how this is more generally useful?
>>>
>> <snip>
>>
>>> terms when I saw the first pair of brackets, so it did not occur to me
>>> to see the second set of brackets as indexing.
>>>
>>> boB
>>>
>>>
>>
>> Steven explained it. I'd point out that wiser snake charmers than I
>> discouraged me (some on this list) from using it from the position that
>> it
>> was too clever. I've done so from time to time anyway; there is a
>> momentary
>> jolt when reading the code months later.
>
>
> I don't know who they were, I certainly hope they didn't include me.

Not so far as I recollect, but it is nearing a decade ago, now. I'll
leave my fuzzy memories where they are. FWIW, as indicated, that's a
bit of advice I didn't always follow.

Best,

Brian vdB