Re: [Visualpython-users] deleting scenes

[Bruce S. <Bru...@nc...>]

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Makes sense; thanks. I considered saying something about del but for no
good reason didn't. <br>
<br>
I should go through all the docs and change 1/0 to True/False. The
history is that in 2000 Python didn't have True/False. At some point
Scherer implemented true=1 and false=0, but the documentation didn't
exploit this. And then even later True/False got added to Python; I
don't remember when that happened.<br>
<br>
Bruce Sherwood<br>
<br>
Guy K. Kloss wrote:
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  <pre wrap="">On Mon, 29 Jun 2009 11:28:22 Bruce Sherwood wrote:
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    <pre wrap="">Here's what I've put into the documentation at vpython.org (and will go
into the documentation that is installed locally for Visual):


To hide a Visual object just make it invisible: ball.visible = 0. This does
not delete the object from computer memory, and you can make it visible
again later.

If however you later re-use the name ball, for example by creating a new
object and naming it ball, Python will be free to release the memory used
by the object formerly named ball (assuming no other names currently refer
to that object). If the object is visible when you re-use the name ball,
the original object will not be deleted from computer memory, and it will
remain visible in the window.

Suggestions for improvement?
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You might want to add something how to explicitly delete items as well. E. g. 
to remove them *now* call "del foobar" after setting the object to 
"obj.visible = False".

BTW, I'd also suggest to use "ball.visible = False" rather than "... = 0". The 
boolean nature is much more expressive, and it also implies that you don't 
have a "value" there, which could be interpreted as visible = 0.5 is like 
opacity and makes it only half visible. This change would remove ambiguity 
straight off the bat.

Guy

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