[SciPy-User] [scipy-user] How to remove a value from an np array?

Fabien Lafont lafont.fabien@gmail....
Mon Jan 30 08:22:01 CST 2012


Sorry to be boring but do you have any idea?

I want to have an array with 2 columns and erase the entire line when
it find a "nan" in the second column?

Thx again,

Fabien

2012/1/27 Fabien Lafont <lafont.fabien@gmail.com>:
> Thx,
>
> I have another. First I expose my problem I have datas like that. Is
> it possible to create an array with two columns and then do something
> to erase the entire line(both time and points) where nan appears?
>
>
> X(Time)     Points
> 1                  5
> 2                 nan
> 3                  3
> 4                  4
> 5                 nan
> ...
>
>
> 2012/1/27 David Warde-Farley <wardefar@iro.umontreal.ca>:
>> On Fri, Jan 27, 2012 at 06:48:45PM +0100, Fabien Lafont wrote:
>>> And how can I remove a specific element designated by its position
>>> numer? like remove(a[8]) for exemple.
>>
>> This is generally not something you want to be doing with NumPy arrays. NumPy
>> arrays represent fixed blocks of memory, removing an element means
>> reallocating the array and copying values before and after position 8 is the
>> only way.
>>
>> If a is one-dimensional, then np.concatenate(a[:8], a[9:]) will do the job,
>> but if you are going to be frequently performing this kind of operation you
>> will get better performance out of a plain Python list.
>>
>> David
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