Re: [Matplotlib-users] dates for x-axis

[questions a. <que...@gm...>]

Thank you, I was able to get it to work but only if I imported datetime
within the loop, otherwise I ended up with the
AttributeError: type object 'datetime.datetime' has no attribute 'datetime'
and if I added 'import datetime' at the top of my script it had an error
where I loop through combining each month
"    stop_month = datetime(2011, 03, 01)
TypeError: 'module' object is not callable"
It seems very messy with importing datetime everywhere but I am not sure
what the problem is. Below is the code I am using that works:


import numpy as np
import matplotlib.pyplot as plt
from numpy import ma as MA
from mpl_toolkits.basemap import Basemap
from datetime import datetime
import os
from StringIO import StringIO
from osgeo import gdal, gdalnumeric, ogr, osr
import glob
from datetime import date, timedelta
import matplotlib.dates as mdates
import time

rainmax=[]
rainmin=[]
rainmean=[]
yearmonthlist=[]
yearmonth_int=[]

OutputFolder=r"E:/test_out/"
GLOBTEMPLATE = r"e:/Rainfall/rainfall-{year}/r{year}{month:02}??.txt"

def accumulate_month(year, month):
    files = glob.glob(GLOBTEMPLATE.format(year=year, month=month))
    monthlyrain=[]
    for ifile in files:
        f=np.genfromtxt(ifile,skip_header=6)
        monthlyrain.append(f)

    import datetime
    yearmonth=datetime.datetime(year,month,1)
    yearmonthlist.append(yearmonth)
    yearmonthint=str(year)+str(month)
    from datetime import date, datetime
    d=datetime.strptime(yearmonthint, '%Y%m')
    date_string=d.strftime('%Y%m')
    yearmonthint=int(date_string)
    yearmonth_int.append(yearmonthint)
    r_max, r_mean, r_min=MA.max(monthlyrain), MA.mean(monthlyrain),
MA.min(monthlyrain)
    rainmax.append(r_max)
    rainmean.append(r_mean)
    rainmin.append(r_min)


###loop through months and years
stop_month = datetime(2011, 12, 31)
month = datetime(2011, 01, 01)
while month < stop_month:
    accumulate_month(month.year, month.month)
    month += timedelta(days=32)
    month = month.replace(day=01)


### Plot timeseries of max data
x=yearmonthlist
y=rainmax
x2=yearmonth_int

print x, y, x2

fig, ax=plt.subplots(1)

z=np.polyfit(x2,y,1)
p=np.poly1d(z)

plt.plot(x,y)
plt.plot(x,p(x2),'r--') #add trendline to plot
print "y=%.6fx+(%.6f)"%(z[0],z[1])

fig.autofmt_xdate()
ax.fmt_xdata=mdates.DateFormatter('%Y%m')
ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y%m'))

plt.xlabel("year-month")
plt.ylabel("Precipitation (mm)")
plt.title("Max monthly precipition")
plt.savefig(OutputFolder+"MaxMonthlyPrecip.png")
plt.show()




On Thu, Apr 19, 2012 at 2:52 AM, Goyo <goy...@gm...> wrote:

> El día 18 de abril de 2012 07:59, questions anon
> <que...@gm...> escribió:
> > I am not exactly sure how to use datetime objects instead of strings.
> > This is the code I am working with at the moment and the code works
> except
> > for the dates, they are just weird numbers along the x-axis.
>
> Seems like you're plotting yearmonthlist in the x axis, which is a
> list of strings and each string is the concatenation of the string
> representations of two numbers. So numbers in the x axis are to be
> expected.
>
> You can create datetime objects this way:
>
> d = datetime.datetime(year, month, 1)
>
> Then create an array of datetime objects and use it as the x parameter to
> plot.
>
> Goyo
>