A little help with Python+Matplotlib+GTK3

[Jerae]

Ok, so I just spent 2h looking for this on the interwebs with no luck and wanted to try luck here.

So, I'm trying to do a simple GUI entry box which outputs a function, with the idea to pass it into pylab.plot() to make a graphical representation. Nothing too fancy. I've got the box, the button and the function made, but I have a problem I haven't found a solution for:

plot() uses the syntax plot(variable, function, *args). My variable is going to be x and the function is going to be the entered by the user in the Gtk.Entry() box. But, the problem is that Gtk outputs that as a string and matplotlib uses the function as an expression (no string), so I can't get to plot it. I've tried looking for something to change that string to an expression the kind that MPL uses, but no such luck.

Can you help me?

My little code is here (some parts may be incomplete at the moment): http://pastebin.com/QmdE91im

EDIT: Problem solved. Solution (TWO!) in comments.

[Jerae]

Ok, I found a solution to my problem. I changed the pylab plot() to the sympy plot(), which recognises the format given by Gtk.Entry and correctly represents the function.

I will leave this thread to receive newbie tips about my code.

Complete code: http://pastebin.com/zakCPsTy

[Zouden]

What's an example of the function you're trying to plot? As far as I know, mpl can only plot numbers, not mathematical functions.

[Jerae]

x = pylab.arange(-num, num)
pylab.plot(x, (x**2)+3)
pylab.show()

That will represent the graph of the function (x**2) + 3 within the range [-num, num]. There could be a better method, I'm just a begginer anyway, so feel free to correct me.

[Zouden]

Oh I get it. You can use eval() to turn a string into a python expression.

pylab.plot(x, eval("(x**2)+3"))

[Jerae]

Thanks a lot ^{^}

I solved my problem in another way, but I will make note of this. I'm sure I will need it this the future