Sudheer, For the documentation you are looking for
print ax1.xcorr.__doc__ (Paul tried to give you the IPython method of getting that documentation which is by typing a ? (or ??) after the desired object.) In the documentation (at the link you gave http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.xcorr), it says that there are three objects returned by xcorr: Return value is a tuple (*lags*, *c*, *line*) where: - *lags* are a length ``2*maxlags+1`` lag vector - *c* is the ``2*maxlags+1`` auto correlation vector - *line* is a :class:`~matplotlib.lines.Line2D` instance returned by :func:`~matplotlib.pyplot.plot`. So the error you were getting is due to the fact that you have only specified two variables to hold the three returned objects. Try: lags,c,line = ax1.xcorr ..... (Note that you have xcorr and lags backwards in your attempt.) -Sterling On Feb 8, 2013, at 1:56AM, Sudheer Joseph wrote: > Thank you verymuch Hobson, > However I think I did not understand > the suggestion by you fully( pardon my ignorance). I use the below test code > from matplotlib site. How does one make a call to get lags and correlation > corresponding to the x and y values in the plot. a Print command of > In [23]: print ax1.xcorr > <bound method AxesSubplot.xcorr of <matplotlib.axes.AxesSubplot object at > 0x44c1410>> > results as above. Is it possible to assign the xcorr,lags=ax1.xcorr(x, y, > usevlines=True, maxlags=50, normed=True, lw=2) ? with a different syntax? I > get below error when I try the above . > In [27]: xcorr,lags=ax1.xcorr(x, y, usevlines=True, maxlags=50, normed=True, > lw=2) > --------------------------------------------------------------------------- > ValueError Traceback (most recent call last) > /home/sjo/work/PY_WORK/stats/<ipython-input-27-e1e58c045ad4> in <module>() > ----> 1 xcorr,lags=ax1.xcorr(x, y, usevlines=True, maxlags=50, normed=True, > lw=2) > > ValueError: too many values to unpack > > > > import matplotlib.pyplot as plt > import numpy as np > x,y = np.random.randn(2,100) > fig = plt.figure() > ax1 = fig.add_subplot(211) > ax1.xcorr(x, y, usevlines=True, maxlags=50, normed=True, lw=2) > ax1.grid(True) > ax1.axhline(0, color='black', lw=2) > ax2 = fig.add_subplot(212, sharex=ax1) > ax2.acorr(x, usevlines=True, normed=True, maxlags=50, lw=2) > ax2.grid(True) > ax2.axhline(0, color='black', lw=2) > plt.show() > > > From: Paul Hobson <pmhob...@gmail.com> > To: Sudheer Joseph <sudheer.jos...@yahoo.com> > Cc: "matplotlib-users@lists.sourceforge.net" > <matplotlib-users@lists.sourceforge.net> > Sent: Thursday, 7 February 2013 10:31 PM > Subject: Re: [Matplotlib-users] cross correlation > > > > > On Thu, Feb 7, 2013 at 3:24 AM, Sudheer Joseph <sudheer.jos...@yahoo.com> > wrote: > Dear Users, > I am relatively new to Matplotlib. I wanted to find cross > correlation between 2 time series for my research and was looking at options > available with python and found > http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.xcorr . However I > wanted to save the results in a netcdf file for further use. ie the > correlation, lags and significance if possible. Is there a way to get the > corr and lags from the axis.xcorr ?? any help in this matter will be greatly > appreciated. > Sudheer > > Sudheer, > > A call to axes.xcorr returns the lags, correlation (from np.correlate) and > the line artists on the figure. > > In IPython, doing "plt.xcorr??" should provide sufficient information. It's a > pretty simple method. > -paul > > > ------------------------------------------------------------------------------ > Free Next-Gen Firewall Hardware Offer > Buy your Sophos next-gen firewall before the end March 2013 > and get the hardware for free! Learn more. > http://p.sf.net/sfu/sophos-d2d-feb_______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
