[Python 2.7.3] What's the difference between these two uses of "for"?

Steven D'Aprano steve+comp.lang.python at pearwood.info
Mon Mar 18 03:44:00 CET 2013

On Sun, 17 Mar 2013 19:14:49 -0700, Yves S. Garret wrote:

> I don't get why it's posting what I said twice...

Because you are emailing to the list, and CCing the list.

In your email, you have:

To: comp.lang.python at googlegroups.com
Cc: python-list at python.org

Unfortunately, they are the same thing. Or rather, when Google Groups 
receives its copy of the email, it then "helpfully" sends another copy to 
python-list at python.org even though you have already CCed it.

In defence of Google Groups, it's not *quite* as stupid as it appears, 
because it's not actually forwarding directly to the same email address. 
It is actually forwarding to the newsgroup comp.lang.python, which is an 
alias to python-list at python.org.

Confused? Don't be. It is very simple: there are at least three ways to 
post to this group:

1) Email to python-list at python.org

2) Post to the news group comp.lang.python on Usenet

3) Email to comp.lang.python at googlegroups.com

There are others as well. Think of them as all aliases to the same 
discussion forum. Whichever you choose, choose ONE ONLY. You are using 
two, hence there are two copies of your message.

I recommend that you choose 1) or 2) rather than Google Groups, if 
possible. There are two problems with Google Groups: 

- it is not very smart, and often mangles messages so that every line is 
separated by a blank line (although I see you have avoided that, at least 
so far!); 

- also, we get a lot of spam and junk advertising coming from Google 
Groups, and so in self-defence many people here have an automatic filter 
that junks anything from Google Groups unread.

If you are unable or unwilling to avoid Google Groups, we will still 
answer your questions, but keep in mind that many of the regulars here 
will not directly see your posts, but only replies to them.


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