vector subscripts in Python?

Gary Herron gherron at islandtraining.com
Thu Jun 12 01:35:14 CEST 2003


On Wednesday 11 June 2003 04:12 pm, beliavsky at aol.com wrote:
> Does Python have the equivalent of "vector subscripts" of Fortran 95?
> The code below illustrates what I am looking for -- with better syntax.
>
> def subscript(xx,ii):
>     # return the elements in xx subscripted by ii
>     y = []
>     for i in ii: y.append(xx[i])
>     return y
>
> ii = [0,2]
> xx = [1,4,9]
> print subscript(xx,ii) # returns [1, 9]; in F95, "print*,xx(ii)" is
> analogous

List comprehension (as it's called) lets you do things like this,
although it's much more general and powerful than your request.

>>> ii = [0,2]
>>> xx =  [1,4,9]
>>> print [xx[i] for i in ii]
[1, 9]
>>>

See the following manual section:
  
http://www.python.org/doc/current/tut/node7.html#SECTION007140000000000000000

Gary Herron








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