matplotlib: Plotting a graph against time

arsyed arsyed at gmail.com
Sun Jul 20 09:55:19 CEST 2008


On Jul 19, 3:09 pm, Durand <dura... at gmail.com> wrote:
> Hi,
>
> I'm trying to plot a simple graph against date or time using matplotlib. I've read about date_plot but I'm not really sure how to use it. At the moment, I have some data arranged into lists, where list1 contains x values (time) and list2 contains y values just like is needed for the normal plot function. The time values are simply the output of datetime.date.today(), etc which I don't mind changing the format of.
>
> My question is, how do I plot the graph with list1 on the x axis and list2 on the y axis. Using plot and unixtime I get a very ugly scale as is to be expected so I want to know how to use the date_plot function efficiently. At the moment, I'm only concerned about the actual plotting but help with Locater Ticks (Months and Years) is also very appreciated.
>
> Thanks a lot!


I'm not sure if this is what you're looking for, but here's a quick
sample that uses plot_date to plot some random values.

import pylab, random
from datetime import datetime, timedelta

today = datetime.now()

dates = [today + timedelta(days=i) for i in range(10)]
values = [random.randint(1, 20) for i in range(10)]
pylab.plot_date(pylab.date2num(dates), values, linestyle='-')





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