converting textobject to name of other object.

[Peter Otten]

Lars Tengnagel wrote:

> I'm trying to use the matrix variable to collect a matrix in the file
> MatrixInfo which contains a lot of different matrices. Yhe commented line
> is the problem.
> HOW ???????

 
> import re
> import MatrixInfo
> 
> class Diff:
>     def __init__(self,filobj,matrix='pam250',begin=0,end='none'):
>         self.fil = filobj
>         self.begin = begin
>         self.end = end

>         if matrix in MatrixInfo.available_matrices:
> ######self.matrix =MatrixInfo.matrix
>             self.matrix= MatrixInfo.pam250
>         else print "matrix don't exist %s" %matrix

Assuming available_matrices_dict is a dictionary with the matrices' name as
keys:

          if matrix in MatrixInfo.available_matrices_dict:
              self.matrix = MatrixInfo.available_matrices_dict[matrix]
          else:
              print "matrix don't exist %s" %matrix    

or a bit more pythonic, since a Diff instance with an unknown matrix
probably doesn't make much sense:

          # you have to handle the exception outside of
          # Diff.__init__()
          self.matrix = MatrixInfo.available_matrices_dict[matrix]

>         self.seqnr=0
>         self.basenr=0
>         self.dict = {}
 
Now how will the available_matrices_dict dictionary come to be?

At the end of MatrixInfo do 

available_matrices_dict = dict([(name, globals()[name]) for name in
available_matrices])

Or you drop the available_matrices list (I suppose) altogether and use a
dict literal instead

available_matrices_dict = {"pam250": pam250, ...}

Peter