array from list of lists

Erin Sheldon erin.sheldon at gmail.com
Sun Nov 12 17:56:29 CST 2006


Hi all-

I want to take the result from a database query,
and create a numpy array with field names and types 
corresponding to the returned columns.

The DBI 2.0 compliant interfaces return lists
of lists. E.g.


[[94137100072000193L, 94, 345.57215100000002, -0.83673208099999996],
 [94137100072000368L, 94, 345.60217299999999, -0.83766954299999996],
 ....
 [94137100083000157L, 94, 347.21668099999999, -0.83572582399999995],
 [94137100084000045L, 94, 347.45524799999998, -0.829750074]]


But the only examples I have found for creating an inhomogeneous
array with fields involves lists of tuples.  e.g.

>>> mydescriptor = {'names': ('gender','age','weight'), 'formats':('S1',
>>> 'f4', 'f4')}
>>> a = array([('M',64.0,75.0),('F',25.0,60.0)], dtype=mydescriptor)

Trying something like this with a list of lists results in
the following error:

TypeError: expected a readable buffer object

Now I could create the array and run a loop, copying
in, but this would be less efficient.  Is there a way
to do this in one step?

Thanks,
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