翻译 Stata 循环

Question

I'd like to translate the following Stata loop to R:

foreach day of numlist 1/7 {;
replace dywt = 1/7 * 1/Freq[`day',1] if interview_day==`day';
}

Data (R Output):

> INTERVIEW_DAY[1:15]
 [1] 5 6 6 4 4 4 1 2 6 4 6 7 6 3 6

> Freq
[1] 0.14353969 0.14795762 0.14089618 0.14074198 0.14194271 0.14295769 0.14196413

> F
[1] 20720

> DYWT[1:15]
 [1] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA

Thank you in advance.

Answer 1

In R , if all of them are vector s, then the equivalent would be to just replace the NA vector ('DYWT') by getting corresponding 'Freq' for each sequence value of 'INTERVIEW_DAY' ( Freq[INTERVIEW_DAY] - as INTERVIEW_DAY is a sequence of numeric vector which can be used as position vector for 'Freq'), divide by 1, and multiply with 1/max(INTERVIEW_DAY)

DYWT <- 1/max(INTERVIEW_DAY) * 1/Freq[INTERVIEW_DAY]

Or if it is based on the number of unique elements, it can be also

DYWT <- 1/length(unique(INTERVIEW_DAY)) * 1/Freq[INTERVIEW_DAY]

or it is 1/7 where 7 is the number of unique elements in 'INTERVIEW_DAY' (if some of the index are missing, then it may be better to use 1/7 )

data

INTERVIEW_DAY <- scan(text = '5 6 6 4 4 4 1 2 6 4 6 7 6 3 6', what = integer())
Freq <- scan(text = '0.14353969 0.14795762 0.14089618 0.14074198 0.14194271 0.14295769 0.14196413', what = numeric())