Hi there,
I'm trying to drop all observations from a subgroup if a variable of only or more of them is negative.
Code:
Basically, the data tracks stock purchases and sells by households. I'm tracking the running inventory in inv, but sometimes that one turns negative (which means stocks are bought before the period). If a stock has negative inventory, all purchases and sells from that stock by that specific investor should be dropped. Any ideas?
Many thanks in advance!
I'm trying to drop all observations from a subgroup if a variable of only or more of them is negative.
Code:
Code:
* Example generated by -dataex-. To install: ssc install dataex clear input long(hhnum permno) float edate str9 date float(quantityb priceb quantitys prices inv) 629 19561 11820 "12may1992" 300 43.75 . . 300 629 19561 13059 "03oct1995" . . 300 66.5 0 629 40707 11611 "16oct1991" 300 40.5 . . 300 629 40707 12387 "30nov1993" 300 26.375 . . 600 629 40707 12417 "30dec1993" . . 300 26.375 300 629 40707 12737 "15nov1994" . . 300 24.125 0 629 43916 13075 "19oct1995" 100 52.5 . . 100 629 43916 13333 "03jul1996" . . 100 39 0 629 51692 12093 "09feb1993" 500 11.25 . . 500 629 51692 12198 "25may1993" . . 500 8.625 0 629 55976 11458 "16may1991" 200 41.0625 . . 200 629 55976 11550 "16aug1991" . . 200 47.25 0 629 55976 13268 "29apr1996" 200 23.5 . . 200 629 56223 13275 "06may1996" 200 27.375 . . 200 629 57795 11806 "28apr1992" 800 12.5 . . 800 629 57795 12015 "23nov1992" 800 7.375 . . 1600 629 57795 12052 "30dec1992" . . 800 7 800 629 57795 12540 "02may1994" . . 800 .375 0 629 62148 11753 "06mar1992" 200 57.5 . . 200 629 62148 11819 "11may1992" . . 200 66 0 629 65568 12501 "24mar1994" 300 13.125 . . 300 629 66069 11491 "18jun1991" 1000 9.375 . . 1000 629 66069 11826 "18may1992" . . 500 12.625 500 629 66069 12079 "26jan1993" . . 500 14.625 0 629 69489 12737 "15nov1994" 300 10.875 . . 300 629 76129 12211 "07jun1993" 200 26.375 . . 200 629 76129 12220 "16jun1993" . . 200 22.25 0 629 77064 12205 "01jun1993" 300 16.375 . . 300 629 77064 12282 "17aug1993" . . 300 14.375 0 629 78203 12222 "18jun1993" 100 42 . . 100 629 78203 12492 "15mar1994" . . 200 22.75 -100 629 78203 12715 "24oct1994" 300 15.5 . . 200 629 79856 12246 "12jul1993" 1000 3.8125 . . 1000 6664 11749 12303 "07sep1993" 800 2.5 . . 800 6664 11749 12436 "18jan1994" . . 800 3.4375 0 6664 76351 13200 "21feb1996" 4000 .625 . . 4000 6664 76809 12269 "04aug1993" 500 5.5 . . 500 6664 76809 12758 "06dec1994" . . 500 3.0625 0 6664 87127 12390 "03dec1993" 200 23.25 . . 200 7980 10775 12214 "10jun1993" 1000 6.375 . . 1000 7980 10775 12395 "08dec1993" . . 1000 6.25 0 7980 75607 12312 "16sep1993" 300 17.5 . . 300 7980 75607 13181 "02feb1996" 300 13.125 . . 600
Many thanks in advance!
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