is a changing background color possible?

matplotlib python: How do you change the background color of a line plot according to a given column? Say I have the following data file

1. 0

4. 0
2. 0
1. 1

2. 1
3. 1
3. 2

1. 2
2. 2

The first column represents the y-values, and the 2nd column should control the background color. Say, it plots the (black) line on a white-gray alternating background (zebra-like) as proceeding further in x-direction, where the transition in color occurs anytime the integer in
the 2nd column increments. Or other possible solution: Use 2nd column as function argument to determine background color.

How would one do this with matlibplot?

Frank


You can use axvspan (see below). You'll need to track where the 2nd
column changes, and then use axvspan to make a colored fill between
(x-1, x). Make sure you pass in a low (< 0) zorder number to the
axvspan function so it stays in the background.

pyplot function:
   http://matplotlib.sourceforge.net/api/pyplot_api.html#matplotlib.pyplot.axvspan

Axes method:
  http://matplotlib.sourceforge.net/api/axes_api.html#matplotlib.axes.Axes.axvspan

Hope that helps,
    Justin

···

On Tue, Jun 21, 2011 at 1:50 PM, Frank <frank.t.winter@...982...> wrote:

matplotlib python: How do you change the background color of a line plot
according to a given column? Say I have the following data file
...
2. 1
3. 1
3. 2

The first column represents the y-values, and the 2nd column should control
the background color. Say, it plots the (black) line on a white-gray
alternating background (zebra-like) as proceeding further in x-direction,
where the transition in color occurs anytime the integer in the 2nd column
increments. Or other possible solution: Use 2nd column as function argument
to determine background color.

How would one do this with matlibplot?