I´ve heard both yok and hayir used as ´no´.  What´s the difference, when do you use one vs the other?
THANKS!

yok means there isn´t hayir means no

yes it ´s right,you can both use ´yok´ and ´hayır´ in the same situation.=it means ´no´

exp:

eve gidecek miyiz?

(will we go home?)

yok gitmeyeceğiz = hayır gitmeceğiz

(No,we will not)

Also,´yok´ means ther is/are not or i have not etc...

Biletin var mı?

(do you have ticket?)

Yok.

(i have not)

=also=

Hayır yok.

(No,I have not.)

is there any problem?

(herhangi bir sorun mu var?)

Yok

(There is not)

Hayır yok.

(No,There is not)

WOW, that is a big help thank you both!

Yok sounds a little more informal to my ears than hayır, and also a little less strong. Yok can be pronounced loosely like ´Yoo´ (the two o´s pronounced slightly seperatedly, and no K at the end), which is less strict/strong than ´hayır´.

Burada sigara içilir mi?

- ´Are cigarettes being smoked here?´ (is smoking allowed here?)

Hayır, burada sigara içilmez.

- No, here cigarettes arent smoked (no, smoking is not allowed here).

Patates kızartması da ister misin?

- Do you also want some fries?

Yok (yoo), gerek yok (yok)

- Nah, there is no need.