Phython and graphing

[mostro]

Hello,

Can someone lead me to an easy way to create a graph in Python.

For example, I have a script running that creates a list of dates,
times and values. I would like to turn this into a graph.

I can grep the info into a new file creating two columns (x,y) but the
issue is the graph.

P.S. I'm a Python newbie so keep that in mind.

Thanks in advance...

 

[Lou Pecora]

Hello,

Can someone lead me to an easy way to create a graph in Python.

For example, I have a script running that creates a list of dates,
times and values. I would like to turn this into a graph.

I can grep the info into a new file creating two columns (x,y) but the
issue is the graph.

P.S. I'm a Python newbie so keep that in mind.

Thanks in advance...

google matplotlib nice package. I've been told that another package
called wsMpl.py also puts a nice API on the matplotlib. You might want
to check that, too.

-- Lou Pecora (my views are my own) REMOVE THIS to email me.

 

[Larry Bates]

Hello,

Can someone lead me to an easy way to create a graph in Python.

For example, I have a script running that creates a list of dates,
times and values. I would like to turn this into a graph.

I can grep the info into a new file creating two columns (x,y) but the
issue is the graph.

P.S. I'm a Python newbie so keep that in mind.

Thanks in advance...

Another possibility would be ReportLab Graphics (www.reportlab.com).
It can create bar charts, line graphs, etc. It is lesser known than
its big brother ReportLab PDF generator, but works equally well. In
addition, it works well if you want to put graphs into .PDF documents.

-Larry Bates

 

[John Hunter]

mostro> Hello, Can someone lead me to an easy way to create a
mostro> graph in Python.

mostro> For example, I have a script running that creates a list
mostro> of dates, times and values. I would like to turn this into
mostro> a graph.

mostro> I can grep the info into a new file creating two columns
mostro> (x,y) but the issue is the graph.

mostro> P.S. I'm a Python newbie so keep that in mind.

Here's an example from the matplotlib examples dir

http://matplotlib.sf.net/examples

that does just that. It loads dates and values from a file using the
load function, and then plots them with the plot_date command

The delimiter directive in the load command says to use comma
separated values. The converters arg is a dictionary mapping column
number to a function that converts that column to a float (datestr2num
converts date strings to matplotlib dates using the wonderful
dateutil.parser.parse function that can convert just about any date
string -- the default column converter is 'float'). skiprows
indicates that there is a single line of header to convert, and
usecols says to take the first and third columns.

The rest is easy -- just call plot_dates:

from pylab import figure, show, datestr2num, load
dates, closes = load(
'data/msft.csv', delimiter=',',
converters={0:datestr2num}, skiprows=1, usecols=(0,2),
unpack=True)

fig = figure()
ax = fig.add_subplot(111)
ax.plot_date(dates, closes)
show()


Here is a brief look at the data file being plotted:

Date,Open,High,Low,Close,Volume,Adj. Close*
19-Sep-03,29.76,29.97,29.52,29.96,92433800,29.79
18-Sep-03,28.49,29.51,28.42,29.50,67268096,29.34
17-Sep-03,28.76,28.95,28.47,28.50,47221600,28.34
16-Sep-03,28.41,28.95,28.32,28.90,52060600,28.74
15-Sep-03,28.37,28.61,28.33,28.36,41432300,28.20
..... and many more


JDH