自己写的一段命令,keep if那句太长了看着就不爽,感觉可以改为循环语句,刚开始学stata比较菜不会,求大神赐教,万分感谢!
gen postcode1=real(postcode)
drop if postcode1==.
gen postcode2=postcode1/10000
gen postcode3=int(postcode2)
keep if postcode3==31 | postcode3==32 | postcode3==21 | postcode3==22 | postcode3==51 | postcode3==52 | postcode3==35 | postcode3==36 | postcode3==43 | postcode3==44 | postcode3==45 | postcode3==46 | postcode3==47