Can one make 'in' ungreedy?
On Mon, May 18, 2020 at 7:05 AM Chris Green <cl at isbd.net> wrote:
> I have a strange/minor problem in a Python program I use for mail
> One of the ways it classifies messages is by searching for a specific
> string in square brackets  in the Subject:, the section of code that
> does this is:-
> # copy the fields from the filter configuration file into better named variables
> nm = fld # name/alias
> dd = fld + "/" # destination directory
> tocc = fld.lower() # list address
> sbstrip = '[' + fld + ']' # string to match in and/or strip out of subject
> # see if the filter To/CC column matches the message To: or Cc: or if sbstrip is in Subject:
> if (tocc in msgcc or tocc in msgto or sbstrip in msgsb):
> # set the destination directory
> dest = mldir + dd + nm
> # Strip out list name (4th field) from subject if it's there
> if sbstrip in msgsb:
> msg.replace_header("Subject", msgsb.replace(sbstrip, ''))
> # we've found a match so assume we won't get another
> So in the particular case where I have a problem sbstrip is "[Ipswich
> Recycle]" and the Subject: is "[SPAM] [Ipswich Recycle] OFFER:
> Lawnmower (IP11)". The match isn't found, presumably because 'in' is
> greedy and sees "[SPAM] [Ipswich Recycle]" which isn't a match for
> "[Ipswich Recycle]".
> Other messages with "[Ipswich Recycle]" in the Subject: are being
> found and filtered correctly, it seems that it's the presence of the
> "[SPAM]" in the Subject: that's breaking things.
> Is this how 'in' should work, it seems a little strange if so, not
> intuitively how one would expect 'in' to work. ... and is there any
> way round the issue except by recoding a separate test for the
> particular string search where this can happen?
>>> sbstrip = "[Ipswich Recycle]"
>>> subject = "[SPAM] [Ipswich Recycle] OFFER:Lawnmower (IP11)"
>>> sbstrip in subject
Clearly something else is going on in your program. I would run it in
the debugger and look at the values of the variables in the case when
it fails when you think it should succeed. I think you will see the
variables do not hold what you think they do.