Unexpected behaviour from ishandle()

1 次查看（过去 30 天）
Temu Gautama
Temu Gautama 2019-11-22
编辑： Stephen23 2019-11-22
Hi,
In a script, I was checking the existence of a plot handle to either make a new plot or to change the x/y data. Surprisingly this didn't work by initially setting the plot handle to []. Reason:
>> ishandle( [] )
ans =
[]
which sort of makes sense.
However, my next step was to initialise the plot handle to 0, which also didn't work, and this was the real surprise:
>> ishandle( 0 )
ans =
1
Even though
>> ishandle( 1 )
ans =
0
Does anybody why zero would be a valid graphics or Java object handle?
Thanks,
Temu

请先登录，再回答此问题。

采纳的回答

Stephen23
Stephen23 2019-11-22
编辑：Stephen23 2019-11-22
On MATLAB versions prior to R2016b zero is the handle to the graphics root (i.e. the parent of all graphics figures):
https://www.mathworks.com/help/matlab/graphics-objects.html
For compatilbility using zero is still permitted in later versions.
https://www.mathworks.com/help/matlab/ref/groot.html

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Startup and Shutdown 的更多信息

标签

产品


版本

R2015b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by