Dear All, I have this data set:
Code:
* Example generated by -dataex-. For more info, type help dataex
clear
input str32 ipc str20 wanted
"H02K21/12 H02K21/24"              "H02K H02K"          
"A61K35/78 A61P39/02"              "A61K A61P"          
"H02J15/00"                        "H02J"               
"C08L23/06 C08K3/34 C08J5/18 C09K" "C08L C08K C08J C09K"
end
For each element of the `ipc' variable, I wish to take the first 4 letters to construct `wanted' variable. Any suggestions? Thanks.