VMD-L Mailing List

From: Axel Kohlmeyer (akohlmey_at_cmm.chem.upenn.edu)
Date: Tue Sep 04 2007 - 09:12:58 CDT

On Tue, 4 Sep 2007, [iso-8859-7] Θωμας [iso-8859-7] Ευαγγελιδης wrote:

TE>
TE>
TE> Hi,
TE>
TE> I need to write a regexp in Tcl to implement a grep command that will match
TE> exactly a line of a pdb file. Specifically, given a resid "13", a segname "SOD"
TE> and a type "ION", I need to get this line from the pdb:
TE>
TE> ATOM 6856 SOD SOD I 10 15.803 8.833 -20.385 1.00 0.00 ION
TE>
TE>
TE> In perl I would write the following regexp:
TE> "^ATOM\ *[0-9]*\ *SOD\ *.*10\ *[\-\.0-9]*\ **[\-\.0-9]*\ **[\-\.0-9]*\
TE> **[\-\.0-9]*\ **[\-\.0-9]*\ *ION\ \ \ $"
TE>
TE> But in Tcl I get an error for each of the following "[0-9]", "*[\-\.0-9]*",
TE> "\ *".
TE>
TE> Can anybody propose a accurate regexp in Tcl please?

please consider the tcl quoting conventions and language constructs.
strings quoted with "" are subject to evaluation and square brackets
are a part of the tcl syntax []. literal strings in tcl have to be
bracketed with curly braces {}. alternately you have to escape
everything that will be expanded in "" context with a backslash.

check out:
http://www.tcl.tk/man/tcl8.5/tutorial/tcltutorial.html

cheers,
   axel.

TE> Thanks,
TE> Thomas Evangelidis
TE>
TE> 

-- 
=======================================================================
Axel Kohlmeyer   akohlmey_at_cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.