is it shoplifting if the merchandise is still in your purse but you havent left the store yet

According to the WV Code §61-3A-1(a) A person commits the offense of shoplifting if, with intent to appropriate merchandise without paying the merchant's stated price for the merchandise, such person, alone or in concert with another person, knowingly:

(1) Conceals the merchandise upon his or her person or in another manner; or

(2) Removes or causes the removal of merchandise from the mercantile establishment or beyond the last station for payment; or

(3) Alters, transfers or removes any price marking affixed to the merchandise; or

(4) Transfers the merchandise from one container to another; or

(5) Causes the cash register or other sales recording device to reflect less than the merchant's stated price for the merchandise; or

(6) Removes a shopping cart from the premises of the mercantile establishment; or

(7) Repudiates a card-not-present credit or debit transaction after having taken delivery of merchandise ordered from the merchant and does not return the merchandise or attempt to make other arrangements with the vendor.

(b) A person also commits the offense of shoplifting if such person, alone or in concert with another person, knowingly and with intent obtains an exchange or refund or attempts to obtain an exchange or refund for merchandise which has not been purchased from the mercantile establishment.

http://www.legis.state.wv.us/WVCODE/Code.cfm?chap=61&art=3A

If you need to consult with a criminal attorney, you can click on the link below:

http://attorneypages.com/524WV/index.htm

Technically, yes.  If you took an item knowing that it does not belong to you and intended not to pay for it, then you have committed the offense.  The crime is complete once you have formed the intent to take something that does not belong to you and intend to make it your own without paying the owner for it.  Not leaving the store is irrelevant to a determination of whether you have committed the underlying offense.  It is your conduct that implicates you, not where you ultimately take the item.