[Tutor] read in ascii and plot

[Wayne Werner]

On Mon, Nov 30, 2009 at 5:55 PM, questions anon <questions.anon at gmail.com>wrote:

> I would like to read in two columns of data from a *.txt file
>
> I type
>
> f=open("e:/testascii.txt")
> import pylab
> pylab.scatter(f)
>
> and then receive an error.
> How do I point it to each column and do I need to do anything about the
> space gap between the two columns?
> Thanks in advance.
>

A sample of the data is always helpful, but I'll take a shot in the dark.

If you have data like this:

2.31     72
98        23
...         ....
34        7.32

And those are x y pairs you could do something like this:

f = open('input.txt')
#List comprehension to read all the lines as [[x1, y1], [x2, y2], ... [xn,
yn]]
data = [line.split() for line in f]
# Reorient values as [(x1, x2,... xn), (y1, y2, ... yn)]
data = zip(*data)
# plot the xy vals
pylab.scatter(data[0], data[1])

That should be something along the lines of what you're looking for.
HTH,
Wayne

-- 
To be considered stupid and to be told so is more painful than being called
gluttonous, mendacious, violent, lascivious, lazy, cowardly: every weakness,
every vice, has found its defenders, its rhetoric, its ennoblement and
exaltation, but stupidity hasn’t. - Primo Levi
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/tutor/attachments/20091130/9e241f80/attachment.htm>