[Numpy-discussion] Selection of only a certain number of fields

Neil neilcrighton@gmail....
Sat Feb 7 08:27:43 CST 2009


Travis E. Oliphant <oliphant <at> enthought.com> writes:

> I've been fairly quiet on this list for awhile due to work and family 
> schedule, but I think about how things can improve regularly.    One 
> feature that's been requested by a few people is the ability to select 
> multiple fields from a structured array.
> 
> Thus,  suppose *arr* is a structured array with dtype:
> 
> [('name', 'S25'),
>   ('height', float),
>   ('age', int),
>   ('gender', 'S8')
> ]
> 
> Then,  newarr = arr[['name', 'age']]  should be a structured array with 
> just the name and age fields.
> 

What are some common use cases for this feature?

I use structured arrays quite a lot, but I haven't found myself wanting
something like this. If I do need a subset of a structured array generally I use
something like 

[rec[n] for n in 'name age gender'.split()]

For me that use case doesn't come up very often though. 




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