Question

Test data and method for determining it is located at: Use of IF function in R

I need to enter the ‘Test’ data into another function. The data for x and y is provided below (essentially two options, 1 = (89.3, 12.1) and 2 = (97.2, 8.5). The equation below is part of much larger function but this is where the problem is. What i want to do is to call each of the values indiviudally from the vector we have (Test) and for the output to be have 2 values for each value in test. When i link Test in directly i receive a new vector with 50 output values which makes no real sense. If i put the first value from the Test vector in, i receive an output of 2 values which is correct (i have checked this manually).

set.seed(1)
Test <- ifelse(runif(50, 0, 1) < 0.69, rnorm(50, 25, 4), rnorm(50, 28, 4.3))


x <- c(89.3, 97.2)
y <- c(12.1, 8.5)

c(-0.75*(((Test)-x)/y)^2)

output is currently this from the above function:

 [1] -21.32750 -55.05068 -25.23216 -49.25087 -20.09236 -53.28421 -19.61593
 [8] -51.81307 -21.32136 -62.68412 -22.28700 -56.50245 -21.33593 -47.71792
[15] -18.53459 -55.10348 -16.12545 -42.79888 -19.73790 -40.38937 -17.77048
[22] -51.94862 -19.20262 -54.78823 -18.92120 -51.75187 -22.82277 -52.08655
[29] -18.82475 -45.86141 -16.28231 -56.33673 -24.02006 -50.75048 -14.97440
[36] -40.67076 -20.51602 -50.05597 -21.04648 -58.66084 -20.32455 -65.47588
[43] -20.01028 -53.19754 -15.84125 -52.88386 -23.09141 -50.51265 -19.73710
[50] -50.32994

but taking the first value from test and putting it in manually gives this:

c(-0.75*(((24.77549)-x)/y)^2)
[1] -21.32750 -54.44958

which is what i want for all 50 values in test

Thanks for any help.

Answer 1

Use sapply:

set.seed(1)
Test <- ifelse(runif(50, 0, 1) < 0.69, rnorm(50, 25, 4), rnorm(50, 28, 4.3))

x <- c(89.3, 97.2)
y <- c(12.1, 8.5)

result = sapply(Test, function(t) c(-0.75*(((t)-x)/y)^2))

result is then a 2×50 matrix:

> result
          [,1]      [,2]      [,3]      [,4]      [,5]      [,6]      [,7]
[1,] -21.32750 -21.59186 -25.23216 -19.04891 -20.09236 -20.81548 -19.61593
[2,] -54.44959 -55.05068 -63.29020 -49.25087 -51.63562 -53.28421 -50.54767
          [,8]      [,9]     [,10]     [,11]     [,12]     [,13]     [,14]
[1,] -20.17012 -21.32136 -24.96341 -22.28700 -22.23106 -21.33593 -18.37988
[2,] -51.81307 -54.43561 -62.68412 -56.62937 -56.50245 -54.46874 -47.71792
         [,15]     [,16]     [,17]     [,18]     [,19]     [,20]     [,21]
[1,] -18.53459 -21.61509 -16.12545 -16.24298 -19.73790 -15.20235 -17.77048
[2,] -48.07270 -55.10348 -42.52723 -42.79888 -50.82633 -40.38937 -46.31876
         [,22]     [,23]     [,24]     [,25]     [,26]     [,27]     [,28]
[1,] -20.22954 -19.20262 -21.47642 -18.92120 -20.14330 -22.82277 -20.29001
[2,] -51.94862 -49.60262 -54.78823 -48.95848 -51.75187 -57.84436 -52.08655
         [,29]     [,30]     [,31]     [,32]     [,33]     [,34]     [,35]
[1,] -18.82475 -17.57154 -16.28231 -22.15805 -24.02006 -19.70470 -14.97440
[2,] -48.73760 -45.86141 -42.88975 -56.33673 -60.55407 -50.75048 -39.86019
         [,36]     [,37]     [,38]     [,39]     [,40]     [,41]     [,42]
[1,] -15.32366 -20.51602 -19.40083 -21.04648 -23.18320 -20.32455 -26.20255
[2,] -40.67076 -52.60188 -50.05597 -53.81015 -58.66084 -52.16534 -65.47588
         [,43]     [,44]     [,45]     [,46]     [,47]     [,48]    [,49]
[1,] -20.01028 -20.77743 -15.84125 -20.63975 -23.09141 -19.60061 -19.7371
[2,] -51.44830 -53.19754 -41.86986 -52.88386 -58.45297 -50.51265 -50.8245
         [,50]
[1,] -19.52067
[2,] -50.32994