keep command

[Raeedur Rahman]

hellow all
i am facing a problem with "keep" command. i got a data which contains 5 to 6 variables,
now i want to keep those data which fill up the two conditions at a time.( like varible1==1 and variable2==1)
please some one help me with necessary command. thamks to all
Regards
Raeed

[Carlo Lazzaro]

Raeedur:
the following example might be helpful:

. set obs 10

. g variable1=1 in 1/5

. replace variable1=2 if variable1==.

. g variable2=1 in 2/7

. replace variable2=2 if variable2==.

. g Flag=1 if variable1==1 & variable2==1

. replace Flag=0 if Flag==.

. keep if Flag==1

[Raeedur Rahman]

male female age occupation
1 0
1 0
1 0
1 0
0 1
0 1
0 1
0 1


dear Sir
if i wana keep those which male==1 no mater what is in female
and also those which female=1 no mate what is in female
i have tried this command (keep if male=="1" female==1) but it says invalide "femail" .
thanks

[Jay Rege]

You have to add | or &

keep if male == 1 & female == 1

for Keep if the Observation is male and female
or

keep if male == 1 | female == 1

for Keep if the Observation is female == 1 OR male == 1

[Raeedur Rahman]

thanks dear JAY

[Raeedur Rahman]

if i have duplicate data and i need to drop one of them .. criteria of drop is (male=1 and female= blank) what should i do?

[Evelyn Ersanilli]

Assuming that the variable female is a numeric 'blank' - more commonly known as 'missing' - is coded in Stata as '.'

so

drop if male==1 & female==.

In Stata, missing values are positive infinity, so you could also tell Stata to only keep cases with a valid value for female by:

keep if female<.
​

Maybe you have already done this, but if not I would advise ensuring all cases that meet the condition 'male==1 & female==.' are indeed duplicates
I would first run a code to identify duplicates and then use a drop command to drop the cases.
You can identify duplicates using Stata's 'duplicates' command. Type 'help duplicates' in the command window to get information on the syntax and some examples.

[Raeedur Rahman]

Evelyn
thanks for your information.. i can't find out any way to drop this problems. i transfer that data to foxpro file use pack command to delete it but i need a sata command that can help me out...
lets see if your provided command can solve my problem
thanks again

[Carlo Lazzaro]

Raeedur:
are you sure that all your variables are in numeric format?