Re: [Matplotlib-users] Problem: Multiple plots with same variables plot incorrectly.

[Christopher B. <Chr...@no...>]

Louis,

This is standard num* array behavior: arrays are mutable, and MPL is not 
making copies of them when you plot, which is a good thing.

by the way, slices of arrays are references too, which is different than 
python lists, so it can be surprising, but also useful

>              # 1st Plot .................
>        x[0]= 1.0
>        y[0]= 1.0
>        x[1]=-1.0
>        y[1]=-1.0
>        a.plot(x,y)
> 
>        # 2nd Plot .................

now you need copies. You can make brand new ones, or use the copy() method:
x = x.copy()
y = y.copy()

you could also pass a copy into the plot method:

a.plot(x.copy(), y.copy())

which is perhaps the behavior you were expecting.

-Chris


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Christopher Barker, Ph.D.
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Chr...@no...