st: encode command and then drop

[Julian Kochan <julian.kochan@gmx.de>]

Hi Statalisters,

i am new to Stata and try to recode strings into numeric Numbers.
I have data of 10.000 firms for the years 2000-2011 such that the first colum displays the firm Key and the second displays the years. 
I wanted to drop certain firms. But the command * drop if Key == C0056 led to "type mismatch".
I though it's probably due to Key coded as string and not as a number.
Now, I want to recode the firm names into numbers. 

I tried 

encode Key, generate (Key2).

I know it is encoded now, but in the data editor it still displays the keys in the variable "Key2" and not the numbers from 1 till 10.000. 
I want to encode in such a way, that I can drop in the following step all firms using the drop if Key== (for example) 2 3 10 65 or 98

Thank you guys
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