CODEWITHSUNDEEP
javascriptjquery
James Dunay
James Dunay

Reputation: 2724

Simple 'if' with 'or' statement

I'm having trouble figuring why this isn't working...

if (index != 10 || index != 0) {

If index = 0 the function is still allowed in, why?

Upvotes: 0

Views: 116

Answers (5)

vvv
vvv

Reputation: 53

You should replace the || with a &&.Not to get confused with the || which is OR operator and is evaluated true if any of the conditions aretrue while the && AND operator evaluates to a true if and only if all the conditions are true.

Upvotes: 0

marramgrass
marramgrass

Reputation: 1411

If index evaluates to a number, one of those conditions will always be true.

Try

if (!(index == 0 || index == 10)) {
    ...
}

Upvotes: 1

christophmccann
christophmccann

Reputation: 4211

Because you are using an OR e.g. ||. So first of all it says does index != 10 which is true since it equals 0 and it therefore proceeds into the conditional.

You would need to change it to (index != 10 && index != 0).

Upvotes: 2

HolyThunder
HolyThunder

Reputation: 463

Yep, it will, since using || means it will run if ANY of the 2 conditions are true. Hence, since 0 is not 10, it will run, because when using || only 1 of the conditions needs to be satisfied.

If you want it to not be allowed, use && instead of ||, this way it will only run if both conditions are satisfied

Upvotes: 1

Rob W
Rob W

Reputation: 349252

When index is zero, it is not ten.

The double pipe is a logical OR operator. The expression returns true when either the left, or the right side is true.

If you intend to return false when index is not 10 and zero, use the logical AND, &&:

if (index != 10 && index != 0) {

Upvotes: 5

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