dropping or keeping variables with wildcard

[Umair Shams]

Ok, so I know that if you type the following Stata will drop all variables that begin with aaa.
. drop aaa*
But what if I want to drop all the variables that contain "aaa". I don't mind using "keep" either if it makes this easier.

Thanks in advance.

[Nick Cox]

It's just *aaa* but check first what you are catching.

clear
set obs 1
foreach v in baaa aaab poohbaaah {
   gen `v' = 42
}

. d *aaa*

              storage   display    value
variable name   type    format     label      variable label
-------------------------------------------------------------------------------
baaa            float   %9.0g                 
aaab            float   %9.0g                 
poohbaaah       float   %9.0g                 

. drop *aaa*

[Umair Shams]

Aaah so simple, just a star at the beginning and another at the end. Thanks so much Nick.