[SciPy-User] Select rows according to cell value
Andreas Hilboll
lists at hilboll.de
Tue Nov 13 11:10:46 EST 2012
Am Di 13 Nov 2012 17:07:19 CET schrieb Juan Luis Cano Rodríguez:
> I am loading some tabular data of the form
>
> alt temp press dens
> 10.0 223.3 26500 0.414
> 10.5 220.0 24540 0.389
> 11.0 216.8 22700 0.365
> 11.5 216.7 20985 0.337
> 12.0 216.7 19399 0.312
> 12.5 216.7 17934 0.288
> 13.0 216.7 16579 0.267
> 13.5 216.7 15328 0.246
> 14.0 216.7 14170 0.228
>
> into an ordinary NumPy array using np.loadtxt. I would like though to
> select the rows according to the altitude level, that is:
>
> >>> data = np.loadtxt('data.txt', skiprows=1)
> >>> altitudes = [10.5, 11.5, 14.0]
> >>> d = ... # some simple syntax involving data and altitudes
> >>> d
> 10.5 220.0 24540 0.389
> 11.5 216.7 20985 0.337
> 14.0 216.7 14170 0.228
>
> I have tried a cumbersome expression which traverses all the array,
> then uses a list comprehension, converts to an array... but I'm sure
> there must be a simpler way. I've also looked at argwhere. Or maybe I
> should use pandas?
>
> Thank you in advance.
>
>
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+1 for using pandas
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