asked on

Is there a Korn shell data type equivlent to Pascal sets?

I know! It's just wishful thinking. Just thought I'd put it out there.

I have a situation for which, if I could use Pascal, I'd define a set type and declare a set variable which I could reference in a construct similar to the following...

SOMETHING = (me, myself, I)
SET = set of SOMETHING
THIS: SET
THAT: SET
readln(THIS)
if THIS in THAT; then...

My Pascal is a little rusty, but...

What I'm trying to do is determine whether one number is included in a set of other numbers. So far, all I've come up with is the case statement:

case $NUMBER in
1|5|9|21|34) Do something or do nothing, as it were...

farzanj

How about?

set="1 5 9 21 34"
if $(echo $set | grep -q "\b$NUMBER\b")
then
     echo do something
fi

Open in new window

ozo

SET='^(1|5|9|21|34)$'
[[ $NUMBER =~ $SET ]] && Do something

SET=" 1 5 9 21 34 "
[[ $SET =~ " $NUMBER " ]] && Do something

Edgar Cole

ASKER

Hmm. I've never seen the '=~' operator. Unfortunately, it doesn't look like my versions of the Korn shell will accept it. I apologize. I forgot to mention that I'm running on AIX 5.3 and 6.1.

ozo

Does your version of ksh support this?

SET=" 1 5 9 21 34 "
[[ ${SET/ $NUMBER } != $SET ]] && Do something

woolmilkporc

SET=" 1 5 9 21 34 "
NUMBER=34
if [[ $(expr index "$SET" "$NUMBER") -ne 0 ]] then
echo Found. Do something.
else
echo Not found. Do nothing.
fi

or

SET=" 1 5 9 21 34 "
NUMBER="34"
if [[ "$SET" == *"$NUMBER"* ]] then
echo Found. Do something.
else
echo Not found. Do nothing.
fi

Unfortunately, the above will also match with e. g. NUMBER="3" (but at least the second one will not match with NUMBER=" 3 "), so I think farzanj's solution is best (so far), but without "\b", because our grep doesn't understand this syntax. Use "-w" (word match) instead:

... grep -wq "$NUMBER" ...

ASKER CERTIFIED SOLUTION

ozo

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