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# Re: [libreoffice-users] random # in calc

```Hi :)
Computers don't usually do "random" very well.

Prolly better to wait until everyone is together (or at least enough
of you that no-one is going to feel the results were "fixed") and then
draw names from a hat.  Print the names on slips of paper and then
make a big show of pulling out a name at random.  A twist is for the
1st winner to pick the 2nd name and then the 2nd winner picks the 3rd
slip.  This twist further minimises accusations of it being "fixed".

You might be able to buy a 20 sided dice from a games shop such as
"Games and Puzzles" (if they still exist) or find one in a box of
"Dungeons and Dragons" or "Runequest" or some-such.
Regards from
Tom :)

On 14 November 2013 09:05, Brian Barker <b.m.barker@btinternet.com> wrote:
```
```At 10:17 11/11/2013 -0500, Helen Etters wrote:
```
```
A LO calc question.  It's a bit trivial, but I'm sure it can be done.
```
```

Have you wondered why you have got little in the way of replies?  Er,
perhaps "Draw names for Christmas gifts" is not a clear definition of a
problem!  You have three presents to give away and you just want pick three
names as gold, silver, and bronze winners - right?  Oh, - or you want to
divide the twenty into two groups, ten givers and ten receivers - right?
No?

```
```We can wait until we're all together in a couple of weeks, and that will
work, ...
```
```

I'm finding it difficult to understand how the subjects' physical presence
will simplify your task.  Are you going to give them random numbers on
pieces of paper and ask them to do a dance to arrange themselves in order by
value?  Is that called Musical Numbers?  That's a sort of Christmas party
I'm not familiar with.

```
```... but can we do this by running a random number generator in calc?
```
```

Very probably.

```
```Type 20 names into column one, then the same names again in column 2, then
run a random number generator to match them up?
```
```

Ah, so you are somehow matching twenty with the same twenty.  What does that
hint to us about your actual needs?  Hmm, let's see now.  Perhaps you want
each of the twenty to give a gift to another of the twenty - and to
randomise the results.  Is that it?

Well, if you randomise the order of one column, as you are perhaps
suggesting, it is possible (quite likely?) that someone will be selected to
give their gift to themselves; is that OK?  Perhaps not.  Let's try to avoid
that and get everyone giving to someone else.  But now we may have another
problem.  In general, each person will give to and receive from different
people, but it may happen that the same people are chosen both ways - so
that one pair of individuals simply exchange presents both ways.  Does that
matter?  Do you see your problem needs more careful specification?

```
```I did something similar to this about a year ago (for a church dinner) but
for the life of me I just can't remember how I did it, and the instructions
I get by googling don't work.  (When I follow those instructions, the
function returns #NAME? in the cell.)
```
```

It's not much help to know that unless you explain what the instructions
were.

There ought to be a neat way to do this, but I don't immediately see one.
Try this slightly messy one:

o Enter the names into column A.  I'm assuming there are twenty.

o Copy these into column B.  (Don't retype or you may create differences.)

o In C1, enter =RAND() and fill this down column C.

o In D1, enter =IF(A1=B1;"Themself!";IF(VLOOKUP(B1;A\$1:B\$20;2;0)=A1;"Each
other!";"")) and fill this down column D.

o Select the data in columns B and C, i.e. the range B1 to C20.

o Go to Data | Sort... .  For "Sort by", select "Column C".  (It doesn't
matter whether you choose Ascending or Descending.)

o Click OK.

o The names in column B have now been randomised, but you will probably find
that column D shows either some people selected to give to themself or some
selected to give to each other.  If so, go to Data | Sort... | OK repeatedly
until column D is blank and shows no problems.  Each time you sort, the
random numbers are recalculated and the order in column B changes.  For
twenty names, you may need a few sorts to clear errors but you should get
there fairly quickly.

o Print columns A and B.  (Set a print range for convenience.)

If you need too many sorts to achieve a result, lose some friends.

I trust this helps.

Brian Barker

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