{OT} Perl Question

.... just a small question concerning a ****-up that I witnessed two days
ago, at the University of Paris, whilst observing matriculations. A
student [1] managed to enroll himself for two different 'options', both
taking place on the same day, at the same time, but in two different
locations. As the person doing the enrollments was using seven different
Word for Windows documents, no one noticed the error until later.

So I decided to try to write something in Perl, to place student names and
options into a hash, and to 'flag' the user, if there is a conflict. Thing
is, the more I get into it, the more it seems to me that what I really need
is SQL, and my knowledge of that particular monstrosity, is weak to say the
least.

So the question is: four hundred students, each student enrolling for eight
different classes. Is this possible without SQL ?


[1] no, it wasn't me !

 

Yes.

HTH.

Paul

 

Yes, that's what the students are doing right now.

 

Organising[1] this sort of information in Word documents is the start of
your problems, at least use a spreadsheet[2].

[1] Tenuous
[2] Although a database of some sort would be better

 

What I envisaged doing, was a hash, feeding in <STDIN> progressively, and
.... oh, ****, I have until next year to do it, so I'll off back to the
books.

 

Fugoff. Nah, I've been mucking around with _Learning Perl_ in my spare
time, and wondering, 'What the **** do I need to know Perl for ??'

Well I don't. But now I at least have an excuse to learn it.

 

Yes. Can't see why hashes can't do it. Get the Camel book for
starters and I'd recommend The Perl Cookbook by the same publishers
for useful bits and bobs.

The learning process goes something like this:

a> Find something to do
1> Try.
2> Fail.
3> Try again
4> Fail some more.

After a few million iterations of the above, it becomes clearer.

 

Le Mon, 29 Sep 2003 15:14:26 +0100, Sean Doherty <> a écrit :

{ snip }

I've got the complete 'Perl' CD-ROM ('learning ..', 'Programming'
...,'cookbook', etc.etc).

The problem isn't that hashes can't do it, it's that my knowledge is not
yet deep enough to allow me to manipulate them the way I want to.
Something like ...

while () {
chomp ($option1 = <STDIN>);
$option1 =~ tr /A-Z/a-z ;
$option1 = $hash{something};
...

.... and there it goes pear-shaped.

Like I say ... now that I know it can be done, it's back to the books.

 

[snip]

I figure if you're going to the trouble of learning Perl, you may as well
learn SQL.

3 tables:

#1: Student (one per student)
#2: Class (holds the class and its weekday/time/duration)
#3: StudentClass (maps between Student and Class for each class attended by
each student)

then query them with a single piece of SQL to find out (in a single
statement) where the time/day conflicts lie. Easy, concise and fast. I'll
write the SQL for you if you like.

 

Steve wrote

Reconcile that to my satisfaction then.

 

{ snip }

Well learning Perl is a pasttime, so no hurry. Then again, as my cat
jumped up behind the server last night, and ripped the keyboard cable out
of the machine (leaving the metallic part in the socket), I now have no
functionning PC at home (and am writing this in a Uni. computer lab).

 

Easy, you just take the whole sentence in context by adding the "if you
like" bit to the end of the last sentence. You can still learn even if
you're given an example to learn from (if you're going to be picky .

 

Steve wrote

pardon?

 

[snip]I'm not qualified I'm afraid.

 

5> Try again
6> Flame everyone else in the world for doing it a different way,
and probably in Python or something.

 

Desmond Coughlan :

It's mind-bogglingly trivial.

 

But what if 2 (or more) people have the same name? I mean, aren't most
French people called Pierre?

 

And how did they come up with 8 classes. I mean you have the obvious
ones...

1 - Surrendering
2 - Eating cheese
3 - Riding bicycles, whilst wearing a string of garlic
4 - Sitting in a cafe, chain smoking
5 - Shrugging

But the other 3 elude me completely.

 

sort

then pipe to awk, store field, read next record and compare

QED.

 

On Mon, 29 Sep 2003 13:42:01 +0000, Desmond Coughlan wrote:

You could do it in almost any language.

I'm on a Perl course this week, so if you haven't cracked it by Friday ask
again and I'll confirm that it's piss easy.