[Numpy-discussion] request for new array method: arr.abs()

David M. Cooke cookedm at physics.mcmaster.ca
Wed Aug 23 16:13:45 CDT 2006

On Wed, 23 Aug 2006 13:51:02 -0700
Sebastian Haase <haase at msg.ucsf.edu> wrote:

> Hi!
> numpy renamed the *function* abs to absolute.
> Most functions like mean, min, max, average, ...
> have an equivalent array *method*.
> Why is absolute left out ?
> I think it should be added .

We've got __abs__ :-)

> Furthermore, looking at some line  of code that have multiple calls to 
> absolute [ like f(absolute(a), absolute(b), absolute(c)) ]
> I think "some people" might prefer less typing and less reading,
> like f( a.abs(), b.abs(), c.abs() ).

> One could even consider not requiring the "function call" parenthesis '()'
> at all - but I don't know about further implications that might have.

eh, no. things that return new arrays should be functions. (As opposed to
views of existing arrays, like a.T)

> PS: is there any performace hit in using the built-in abs function ?

Shouldn't be: abs(x) looks for the x.__abs__() method (which arrays have).

|David M. Cooke                      http://arbutus.physics.mcmaster.ca/dmc/
|cookedm at physics.mcmaster.ca

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