CODEWITHSUNDEEP
stata
zlqs1985
zlqs1985

Reputation: 529

Randomly picking years within a time interval

I would like to randomly pick 3 years in a subset of my data, say between 2007 to 2016, except 2008, 2012 and 2014. I want to repeat this process 500 times.

How can I do this simulation while meeting the required conditions?

Note that this is a follow up question to a previous post of mine where I was offered a solution for an unconditional case.

Upvotes: 1

Views: 164

Answers (2)

Romalpa Akzo
Romalpa Akzo

Reputation: 599

The sample command might be a good choice for this issue:

generate tag = !inlist(year, 2008, 2012, 2014)
keep if tag

expandcl 500, generate(ex) cluster(tag)

set seed 582019
sample 3, by(ex) count

Upvotes: 0

user8682794
user8682794

Reputation:

The easiest way is to first subset your data:

sysuse uslifeexp, clear
set seed 12345

// preserve

keep if year >= 1946 & year <=1957
drop if inlist(year, 1948, 1952, 1954)

tempname sim
postfile `sim' id year1 year2 year3 using results, replace

forvalues i = 1 / 500 {
    generate random = runiform()
    sort random
    post `sim' (`i') (year[1]) (year[2]) (year[3])
    drop random
}

postclose `sim'

// restore

Note the commented out preserve / restore commands, which can keep your data intact in case you do not want to only have the reduced dataset after the simulation.

As before the results are stored in a new dataset result:

use results, clear

list in 1/10

     +----------------------------+
     | id   year1   year2   year3 |
     |----------------------------|
  1. |  1    1955    1953    1946 |
  2. |  2    1953    1946    1949 |
  3. |  3    1949    1953    1946 |
  4. |  4    1949    1957    1956 |
  5. |  5    1946    1951    1950 |
     |----------------------------|
  6. |  6    1953    1946    1951 |
  7. |  7    1957    1947    1946 |
  8. |  8    1949    1957    1947 |
  9. |  9    1947    1956    1949 |
 10. | 10    1953    1949    1957 |
     +----------------------------+

Upvotes: 1

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