How do I combine instance+string for variable

[Marc]

Hi all,

I can't remember how to do this.

I have several instances of telnet connections that I label
conn2,conn3, etc. Later when I want to scroll through all of these I
wanted to do something like this:

for int in range(2, 9):
use... conn+str(int) {I'm passing it into another
function}

I can't get it to work. I've tried using setattr and eval, but nothing
seems to work. Can I get a little help.

Thanks ahead of time,
Marc

[Bengt Richter]

Re: How do I combine instance+string for variable

On 1 Aug 2003 14:05:19 -0700, mnations@airmai l.net (Marc) wrote:
[color=blue]
>Hi all,
>
>I can't remember how to do this.
>
>I have several instances of telnet connections that I label[/color]
How do you "label" them? By assigning, like conn2 = someSourceOfCon n(...)?
[color=blue]
>conn2,conn3, etc. Later when I want to scroll through all of these I
>wanted to do something like this:
>
> for int in range(2, 9):[/color]
^^^-- BAD name!! you are shadowing the builtin int.[color=blue]
> use... conn+str(int) {I'm passing it into another
>function}[/color]
Do you want to pass a name in the form of a string, like 'conn2' or do you
want the conn2 that you assigned before?

<untested>
If you know the names, you could just write

for aConn in (conn2, conn3, ..., conn8): # filling in the rest in place of '...'
usingFunc(aConn )

If you had stored the conn's in a list instead of individual names, you could write

for aConn in theList:
usingFunc(aConn )

If you want to pick them up by generated string name from the local namespace, you could write
something like you started with, e.g.,

for i in range(2, 9):
name = 'conn%s' % i
aConn = vars()[name] # or use globals() in place of vars() if not in local namespace
usingFunc(aConn )

or in one line
for i in range(2, 9): usingFunc(vars( )['conn%s'%i]) # ditto re globals() vs vars()

</untested>

[color=blue]
>
>I can't get it to work. I've tried using setattr and eval, but nothing
>seems to work. Can I get a little help.[/color]

Post the code that creates the conn2 etc bindings if the above does not work for you.

Regards,
Bengt Richter

[Marc]

Re: How do I combine instance+string for variable

> >I have several instances of telnet connections that I label[color=blue]
> How do you "label" them? By assigning, like conn2 = someSourceOfCon n(...)?[/color]

Exactly. They are each separate instances of a telnet connection:

conn2 = telnetlib...
....
conn8 = telnetlib...
[color=blue]
> Do you want to pass a name in the form of a string, like 'conn2' or do you
> want the conn2 that you assigned before?[/color]

Actually right now I'm using the list method:

<snippett>
conns = [conn2, conn3, conn4, conn5, conn6, conn7, conn8]
....
for int in range(2,9):
qput(key.comman d, conns[int-2], act_user("user-ID" + str(int), "CTAG",
"t*sting" + str(int) ) )
<end of snippett>

I didn't include the code originally because it goes off in a lot of
directions. I'm putting it into a queue with function qput that later gets
executed with a function in file key.

The list method works for me with a small number of connections, but if I
ever need a lot of connections it will be a little klunky. Therefore I was
trying to find a fix similar to using setattr if I was using classes. So
basically I want to be able to use the conn2 that I assigned before, but
referencing it using a string.

I think the method you mentioned:

for i in range(2, 9):
name = 'conn%s' % i
aConn = vars()[name] # or use globals() in place of vars() if not
in local namespace
usingFunc(aConn )

is what I'm looking for as it appears to concatenate "conn" with a number to
create the instance name. I hadn't come across the built-in function "vars"
yet, but I was trying to accomplish the same thing using "eval".

Thanks for the tip,
Marc

[Terry Reedy]

Re: How do I combine instance+string for variable

> <snippett>[color=blue]
> conns = [conn2, conn3, conn4, conn5, conn6, conn7, conn8]
> ...
> for int in range(2,9):
> qput(key.comman d, conns[int-2], act_user("user-ID" + str(int),[/color]
"CTAG",[color=blue]
> "t*sting" + str(int) ) )
> <end of snippett>[/color]

And what happens if you follow 'snippett' with anything like
type(var)==int # or
var=int(num/3) # or
num = int(somestring)
or preceed it with something like
for str in stringlist: .....
?

Please don't use type names (or other builtins) as variables in posted
code.
Experts may survive it, but it's a bad example for beginners. ;-)

Terry J. Reedy