How to plot only points which lie in a certain range

Community matplotlib-users
1

I'm sorry for this newbie question. I have a data file consisting of 3
columns, and want to plot the first versus the second column, but only if
the parameter in the third column lies in a certain range. Does somebody
have an idea how to do that?

···

--
View this message in context: http://www.nabble.com/How-to-plot-only-points-which-lie-in-a-certain-range-tp20178863p20178863.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

2

Using masked arrays ?
import numpy as np
import numpy as ma
import matplotlib.pyplot as mpl

x = ma.arange(10)
y = ma.array(np.random.rand(10))
z = ma.array(np.random.rand(10))
(z_lo, z_up) = (0.1, 0.8)
x[ (z<z_lo) | (z>z_up) ] = ma.masked
mpl.plot(x,y, 'ok-')

Alternatively,

x = ma.masked_where((z<z_lo) | (z>z_up), x)

···

On Monday 27 October 2008 18:40:07 marcusantonius wrote:

I'm sorry for this newbie question. I have a data file consisting of 3
columns, and want to plot the first versus the second column, but only if
the parameter in the third column lies in a certain range. Does somebody
have an idea how to do that?

3

You need to use the numpy ‘where’ functionality

import numpy as np

x, y, z = np.loadtxt(“fileName.dat”,
unpack=True) # or similar

x, y and z are now numpy arrays and

have built in functionality as follows:

s = (z < 10.0) & (z**2 > 0.5)

or some other constraint. Produces an array ‘s’ of boolean

values

plot(x[s], y[s]) # will plot only
those x,y pairs for which s is True

marcusantonius <markus.haider@…2356…>
28/10/2008 09:40 AM

To

matplotlib-users@lists.sourceforge.net
cc

Subject

[Matplotlib-users] How to plot only
points which lie in a certain range

`

I’m sorry for this newbie question. I have a data file consisting of 3

columns, and want to plot the first versus the second column, but only
if

the parameter in the third column lies in a certain range. Does somebody

have an idea how to do that?

···

–

View this message in context: http://www.nabble.com/How-to-plot-only-points-which-lie-in-a-certain-range-tp20178863p20178863.html

Sent from the matplotlib - users mailing list archive at Nabble.com.

This SF.Net email is sponsored by the Moblin Your Move Developer’s challenge

Build the coolest Linux based applications with Moblin SDK & win great
prizes

Grand prize is a trip for two to an Open Source event anywhere in the world

http://moblin-contest.org/redirect.php?banner_id=100&url=/

Matplotlib-users mailing list

Matplotlib-users@lists.sourceforge.net

https://lists.sourceforge.net/lists/listinfo/matplotlib-users

This email has been scanned by the MessageLabs Email Security System.

For more information please visit http://www.messagelabs.com/email

`

UNITED GROUP

This email message is the property of United Group. The information in this email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this email by anyone else is unauthorised. If you are not the intended recipient, you may not disclose, copy or distribute this email, nor take or omit to take any action in reliance on it. United Group accepts no liability for any damage caused by this email or any attachments due to viruses, interference, interception, corruption or unauthorised access.

If you have received this email in error, please notify United Group immediately by email to the sender’s email address and delete this document.