From: Ashar Malik (asharjm_at_gmail.com)
Date: Wed Jun 03 2020 - 23:53:46 CDT

One way would be

set a apple
# split $a by character
[split $a ""]
# it then becomes a list so you can use lrange
[lrange [split $a ""] 0 2]
# app has index from 0 till 2. but the output of the above is a list - to
get app use join
[join [lrange [split $a ""] 0 2] ""]

the last command will return "app" (from index 0 to 2)

final code

set a apple
puts [join [lrange [split $a ""] 0 2] ""]

On Thu, Jun 4, 2020 at 12:24 PM Prathit Chatterjee <
pc20apr_at_remove_yahoo.co.in> wrote:

> Dear VMD experts,
>
> This is regarding selecting selected characters of a variable with tcl
> scripting in VMD.
> I want to select first few characters of a variable, for example, first
> three characters (app) of the variable "apple":
> ======
> vmd > set a apple
> apple
> vmd > string length $a
> 5
> ======
> I am trying to play around with the command string but could not figure
> out so far.
>
> Any relevant comments/suggestions will be greatly appreciated.
> Thank you in advance,
> Regards,
> Prathit
>
>

-- 
Best,
/A