How to reshape from long to wide in stata

[Ashish Bandhu]

Hi Statalist,

This is my first post.

I have a single variable called random_variable containing random numbers, say, from 1 to 100 but may not be sequentially ( maybe 1, 7, 2). I want to create 15 new variables in the data set each one containing the first 7 (7 may be arbitrary, example is for weekdays) entries from random_variable except the 15th one which will contain only 2 entries. (14*7=98 + 2 in last column).

example
random_variable
1
7
2
.
.
.
up to 100 observations.
.


Anticipating your help

Ashish

[Tiago Pereira]

forvalues i = 1/15 {
    gene new_`i'  = cond(_n<=7,random_variable,.)
    }
    replace new_15 = . if _n>2

Hope this helps!

Tiago

[Ashish Bandhu]

Tiago Pereira, Thanks for reply . The code you shared is not working. For Simplicity I have kept 0nly 18 observation in random_variable and tried for 3 new variables having 7 observations each (7*2=14+4 in last variable)

forvalues i = 1/3 {
gene new_`i' = cond(_n<=7,random_variable,.)
}
replace new_3 = . if _n>4



Please have a look

clear
input double random_variable
1
2
5
7
10
11
34
56
23
31
89
96
56
45
38
90
13
21
end

Actual Outcome

random_variable new_1 new_2 new_3
1 1 1 1
2 2 2 2
5 5 5 5
7 7 7 7
10 10 10 10
11 11 11 11
34 34 34 34
56
23
31
89
96
56
45
38
90
13
21


Expected Outcome


random_variable new_1 new_2 new_3
1 1 56 38
2 2 23 90
5 5 31 13
7 7 89 21
10 10 96
11 11 56
34 34 45
56
23
31
89
96
56
45
38
90
13
21


Ashish

[Tiago Pereira]

You were not clear at the beginning.
"containing the first 7 (7 may be arbitrary, example is for weekdays)"

So, containing 7 numbers chosen at random.

clear
input double random_variable
1
2
5
7
10
11
34
56
23
31
89
96
56
45
38
90
13
21
end


    forvalues i = 1/15 {
        preserve
        sample 7, count
        tempfile new_`i'
        rename random_variable new_`i'
        save `new_`i'', replace
        restore
    }

    forvalues i = 1/15 {
    merge 1:1 _n  using `new_`i''
    cap drop _merge
    }

[Ashish Bandhu]

random.docxSorry Tiago Pereira for not clarity. In my question. In your reply #4, You have mentioned the command sample that I don't want. I want to generate 15 new variables each containing 7 observations from the random_variable that contains 100 random observations. So the first new variable should contain the first 7 observations from the random variable, the second new variable should contain the next 7 observations from the random variable, and so on. I have attached the image file for simplicity .

[Tiago Pereira]

clear
set obs 105
gene random_variable = _n
gene x = runiform()
sort x
cap drop x
seq group, f(1) t(15) b(7)
sort group

    forvalues i = 1/15 {
    preserve
    keep if group == `i'
    cap drop group
    tempfile new_`i'
    rename random_variable new_`i'
    save `new_`i'', replace
    restore
    }
    
    
    
    forvalues i = 1/15 {
    merge 1:1 _n  using `new_`i''
    cap drop _merge
    }
    
    cap drop group

[Ashish Bandhu]

Tiago Pereira , Thank you for continuous support, I tried but found an error in the code "seq group, f(1) t(15) b(7)". Stata does not recognize this seq command. is it seq () ?

[Nick Cox]

seq is a community-contributed command from 1997 and was in essence superseded by the seq() function of egen.

.     search dm44, entry historical

Search of official help files, FAQs, Examples, and Stata Journals

STB-37  dm44  . . . . . . . . . . . . . . . . . . . . .  Sequences of integers
        (help seq if installed) . . . . . . . . . . . . . . . . . .  N. J. Cox
        5/97    pp.2--4; STB Reprints Vol 7, pp.32--33
        egen now has seq() function

[Tiago Pereira]

You can adapt the code following Nick's wise advise. Alternatively, you can type:

 ssc install seq

[Ashish Bandhu]

Thank you both for helping me out.