matplotlib-users

[Matplotlib-users] how to plot stepwise lines

[Zhang Le <zha...@gm...>]

Hello,
  I want to plot a stepwise line using
plot([1,2,3,4,5],[2,-2,2,-2,2]). But what I get is something like two
triangular like shape. But I want a stepwise shape that has steep
vertical jumps. How can I do that?
 Many thanks,
Zhang Le

Re: Spam: [Matplotlib-users] how to plot stepwise lines

[Peter G. <pgr...@ge...>]

>  I want to plot a stepwise line using
>plot([1,2,3,4,5],[2,-2,2,-2,2]). But what I get is something like two
>triangular like shape. But I want a stepwise shape that has steep
>vertical jumps. How can I do that?
>  
>

this what you mean?

#!/usr/bin/env python
from pylab import *

plot([1,2,3,4,5],[2,-2,2,-2,2], linestyle='steps')
gca().set_ylim( (-3, 3))
show()



> Many thanks,
>Zhang Le
>
>
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Peter Groszkowski         Gemini Observatory
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Re: [Matplotlib-users] how to plot stepwise lines

[Alan G I. <ai...@am...>]

It sounds like you want step_pts from
http://www.american.edu/econ/pytrix/pytrix.py
Maybe.
Alan Isaac

def step_pts(x, y):
=09'''Given x and y, return points for step function plot.

=09:Parameters:
=09 - `x`: [x0,x1,...,xn] list of x values (first coordinate)
=09 - `y`: [y0,y1,...,yn] list of y values (second coordinate)
=09:rtype: tuple of lists
=09:return: (xnew,ynew)
=09=09where xnew=3D(x0,x1,x1,...,xn,xn) and ynew=3D(y0,y0,y1,y1,...,yn).
=09:author:    Alan G. Isaac
=09:since: 2005-05-15
=09'''=20
=09pts=3Dzip(x,y)  #original points as tuples
=09inter =3D zip(x[1:],y[:-1]) #new points as tuples
=09#now splice pts and inter -> list of all points as tuples
=09pts_inter =3D [j for i in map(None,pts,inter) for j in i][:-1]
=09#split the points list into (x-coordinates),(y-coordinates)
=09z =3D zip(*pts_inter)=20
=09return z[0],z[1]