gnuplot-py-users

[Gnuplot-py-users] Passing the Value of a Variable to Gnuplot-py

[Richard L. <la...@un...>]

In a Python script, I compute the value of a variable. Let's call it cep. I then want to draw a circle whose radius is cep. I would like to have something like

cep = (some calculation producing a float value)
g('set parametric')
g('set trange [0:2*pi]')
g('fx(t) = cep*cos(t)')
g('fy(t) = cep*sin(t)')
e = Gnuplot.Func('fx(t),fy(t)')
g.plot(e)

but that doesn't work, it seems, as gnuplot doesn't know the value of cep ("undefined variable: cep"). So how does one pass an arbitrary variable value to gnuplot-py?

-- Richard Langley

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| Richard B. Langley                            E-mail: la...@un...         |
| Geodetic Research Laboratory                  Web: http://gge.unb.ca      |
| Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142   |
| University of New Brunswick                   Fax:      +1 506 453-4943   |
| Fredericton, N.B., Canada  E3B 5A3                                        |
|        Fredericton?  Where's that?  See: http://www.fredericton.ca/       |
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Re: [Gnuplot-py-users] Passing the Value of a Variable to Gnuplot-py

[Michael H. <mh...@al...>]

On 12/10/2013 04:54 AM, Richard Langley wrote:
> In a Python script, I compute the value of a variable. Let's call it
> cep. I then want to draw a circle whose radius is cep. I would like to
> have something like
> 
> cep = (some calculation producing a float value)
> g('set parametric')
> g('set trange [0:2*pi]')
> g('fx(t) = cep*cos(t)')
> g('fy(t) = cep*sin(t)')
> e = Gnuplot.Func('fx(t),fy(t)')
> g.plot(e)
> 
> but that doesn't work, it seems, as gnuplot doesn't know the value
> of cep ("undefined variable: cep"). So how does one pass an arbitrary
> variable value to gnuplot-py?

g('cep = %s' % (cep,))

There is no shortcut for this, but it wouldn't be difficult to build one.

Michael

-- 
Michael Haggerty
mh...@al...
http://softwareswirl.blogspot.com/

Re: [Gnuplot-py-users] Passing the Value of a Variable to Gnuplot-py

[Richard B. L. <la...@un...>]

Thanks, Michael. Works!
-- Richard

On Tuesday, December 10, 2013,344, at 3:53 AM, Michael Haggerty wrote:

> On 12/10/2013 04:54 AM, Richard Langley wrote:
>> In a Python script, I compute the value of a variable. Let's call it
>> cep. I then want to draw a circle whose radius is cep. I would like to
>> have something like
>> 
>> cep = (some calculation producing a float value)
>> g('set parametric')
>> g('set trange [0:2*pi]')
>> g('fx(t) = cep*cos(t)')
>> g('fy(t) = cep*sin(t)')
>> e = Gnuplot.Func('fx(t),fy(t)')
>> g.plot(e)
>> 
>> but that doesn't work, it seems, as gnuplot doesn't know the value
>> of cep ("undefined variable: cep"). So how does one pass an arbitrary
>> variable value to gnuplot-py?
> 
> g('cep = %s' % (cep,))
> 
> There is no shortcut for this, but it wouldn't be difficult to build one.
> 
> Michael
> 
> -- 
> Michael Haggerty
> mh...@al...
> http://softwareswirl.blogspot.com/

-----------------------------------------------------------------------------
| Richard B. Langley                            E-mail: la...@un...         |
| Geodetic Research Laboratory                  Web: http://gge.unb.ca/     |
| Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142   |
| University of New Brunswick                   Fax:      +1 506 453-4943   |
| Fredericton, N.B., Canada  E3B 5A3                                        |
|        Fredericton?  Where's that?  See: http://www.fredericton.ca/       |
-----------------------------------------------------------------------------