st: Deleting similar observations

[George Chioran <george_chioran@yahoo.com>]

Dear statlisters, 
I have a database that
looks like this: 
Account               Buy sell
2                              b
2                              b
2                              s
2                              b
5                              s
5                              s
5                              s
5                              s
7                              s
7                              s
Taken per account, I would like to know if
there is a way to delete all the observations that have the same letter in
the Buy sell variable. In my case this would delete all observations from
account 5 since they are all only sell. 
 
Thank you, 
George 


      
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