Skip to main content

Pandas, multiindex, date, HDFstore and frame_tables

Currently if you have a dataframe with a multiindex with a date as one of the indexers you can not save it as a frame_table. Use datetime instead.
import pandas as pd, numpy, datetime

print pd.__version__ #-> 0.13.0rc1

idx1 = pd.MultiIndex.from_tuples([(datetime.date(2013,12,d), s, t) for d in range(1,3) for s in range(2) for t in range(3)])
df1 = pd.DataFrame(data=numpy.zeros((len(idx1),2)), columns=['a','b'], index=idx1)
#-> If you want to save as a table in HDF5 use datetime rather than date


with pd.get_store('test1.h5') as f:
  f.put('trials',df1) #-> OK

with pd.get_store('test2.h5') as f:
  f.put('trials',df1,data_colums=True,format='t') #-> TypeError: [date] is not implemented as a table column

#-> Solution is to use datetime

Update: Thanks to Jeff again for the solution

Comments

Popular posts from this blog

Flowing text in inkscape (Poster making)

You can flow text into arbitrary shapes in inkscape. (From a hint here).

You simply create a text box, type your text into it, create a frame with some drawing tool, select both the text box and the frame (click and shift) and then go to text->flow into frame.

UPDATE:

The omnipresent anonymous asked:
Trying to enter sentence so that text forms the number three...any ideas?
The solution:
Type '3' using the text toolConvert to path using object->pathSize as necessaryRemove fillUngroupType in actual text in new text boxSelect the text and the '3' pathFlow the text

Python: Multiprocessing: passing multiple arguments to a function

Write a wrapper function to unpack the arguments before calling the real function. Lambda won't work, for some strange un-Pythonic reason.


import multiprocessing as mp def myfun(a,b): print a + b def mf_wrap(args): return myfun(*args) p = mp.Pool(4) fl = [(a,b) for a in range(3) for b in range(2)] #mf_wrap = lambda args: myfun(*args) -> this sucker, though more pythonic and compact, won't work p.map(mf_wrap, fl)

Drawing circles using matplotlib

Use the pylab.Circle command

import pylab #Imports matplotlib and a host of other useful modules cir1 = pylab.Circle((0,0), radius=0.75, fc='y') #Creates a patch that looks like a circle (fc= face color) cir2 = pylab.Circle((.5,.5), radius=0.25, alpha =.2, fc='b') #Repeat (alpha=.2 means make it very translucent) ax = pylab.axes(aspect=1) #Creates empty axes (aspect=1 means scale things so that circles look like circles) ax.add_patch(cir1) #Grab the current axes, add the patch to it ax.add_patch(cir2) #Repeat pylab.show()