### Re: Multiple numeric not or compare in if statement

by syphilis (Bishop)
 on Jul 02, 2020 at 05:08 UTC Need Help??

if ((\$a != 3) || (\$a != 77) || (\$a != 8))

```if ((\$a != 3) && (\$a != 77) && (\$a != 8))

Cheers,
Rob

Replies are listed 'Best First'.
Re^2: Multiple numeric not or compare in if statement
by perlfan (Priest) on Jul 02, 2020 at 05:32 UTC
OP: maybe it was an oversight, but when changing the nested logic in a condition such as that you must necessarily change the higher level logic if you wish for the original to be equivalent exactly opposite to the negated version.

```if ((\$a == 3) || (\$a ==  77) || (\$a == 8))
-- is exactly opposite to --
if ((\$a != 3) && (\$a !=  77) && (\$a != 8))

Update: correct - meant to show exact opposites, used the most wrong possible to describe this.

```if ((\$a == 3) || (\$a ==  77) || (\$a == 8))
-- is equivalent to --
if ((\$a != 3) && (\$a !=  77) && (\$a != 8))

No, those two aren't equivalent, they're exact opposites. It seems you didn't apply what you said:

when changing the nested logic in a condition such as that you must necessarily change the higher level logic if you wish for the original to be equivalent to the negated version.
```if ((\$a == 3) || (\$a ==  77) || (\$a == 8))
-- is equivalent to --
if (!( (\$a != 3) && (\$a !=  77) && (\$a != 8) ))
Thanks, updated. Meant to show the exact opposite; said the opposite thing instead.

Create A New User
Node Status?
node history
Node Type: note [id://11118784]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others scrutinizing the Monastery: (4)
As of 2020-08-10 16:19 GMT
Sections?
Information?
Find Nodes?
Leftovers?
Voting Booth?
Which rocket would you take to Mars?

Results (58 votes). Check out past polls.

Notices?