Re: [Gretl-users] Python and Gretl

On Sat, Jan 26, 2013 at 2:18 PM, Allin Cottrell <cottrell(a)wfu.edu&gt; wrote: > On Sat, 26 Jan 2013, Pietro Battiston wrote: > > > I love Gretl's "foreign" code blocks capability, and would love even > > more the possibility of using Python in them, which was at some time > > suggested as easy to implement. > > Yes, quite easy. In fact, so easy that Python support is now > in gretl CVS and the snapshots for Windows and OS X. Here's a > trivial example: > Cool. Thanks. Is there any way to browse this changeset in the repository through the web interface? Git/github has eroded all of my other version control skills.

> > <hansl> > matrix M = I(5) > mwrite(M, &quot;(a)dotdir/pytest.mat&quot;) > foreign language=python > G = gretl_loadmat('pytest.mat') > G *= 5 > gretl_export(G, 'pyout.mat') > end foreign > matrix pymat = mread(&quot;(a)dotdir/pyout.mat&quot;) > print pymat > </hansl> > > When you call python via gretl's "foreign" mechanism you have > three gretl_ functions available: > > gretl_loadmat(): reads a matrix, as written by gretl's > mwrite(), from gretl's per-user dotdir. > > gretl_export(): writes a matrix, readable via gretl's mread(), > into the gretl dotdir. > > gretl_dotdir(): in case you need it, gives the dotdir path. > > When python is invoked via gretl, one thing that happens > automatically is: > > import numpy as np > > This is in part because numpy is needed for the implementation > of gretl_loadmat and gretl_export, which use np.loadtxt and > np.savetxt respectively. I'm not a python person, but I > suspect that some users might not like the "import" statement > as I have it. Comments welcome. > This is the preferred import convention for numpy, so there's no reason to not like it from a style standpoint. Are you concerned with this or the importing the kitchen sink aspect? > > Related question: in Python, as in R, Octave and Ox, the > "dotdir" business (which ensures we have a user-writable and > gretl-findable location) is hidden from the matrix read/write > functions, but on the gretl end you have to use @dotdir > explicitly with mwrite and mread when interfacing with > "foreign". > > Any sale for a pair of gretl functions mexport() and mimport() > which handle the prepending of dotdir automatically? > > Allin Cottrell > > > > _______________________________________________ > Gretl-users mailing list > Gretl-users(a)lists.wfu.edu > http://lists.wfu.edu/mailman/listinfo/gretl-users >