array from list of lists

Erin Sheldon erin.sheldon at gmail.com
Mon Nov 13 01:07:29 CST 2006


On 11/13/06, Charles R Harris <charlesr.harris at gmail.com> wrote:
>
>
> On 11/12/06, Erin Sheldon <erin.sheldon at gmail.com> wrote:
> > Hi all -
> >
> > Thanks to everyone for the suggestions.
> > I think map(tuple, list) is probably the most compact,
> > but the list comprehension also works well.
> >
> > Because map() is proably going to disappear someday, I'll
> > stick with the list comprehension.
> >   array( [tuple(row) for row in result], dtype=dtype)
> >
> > That said, is there some compelling reason that the array
> > function doesn't support this operation?
>
> My understanding is that the array needs to be allocated up front. Since the
> list comprehension is iterative it is impossible to know how big the result
> is going to be.

Isn't it the same with a list of tuples?  But you can send that directly to the
array constructor.  I don't see the fundamental difference, except that the
code might be simpler to write.

>
> BTW, it might be possible to use fromfile('name', dtype=dtype) to do what
> you want if the data is stored by rows in a file.

I'm reading from a database.
Erin

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642




More information about the Numpy-discussion mailing list