simplifing part of function code

Question

I have very simple question, lets say i have function that generates random integer from chosen range, without generating zero. It goes like this:

customfunction=function(minv,maxv){
  value=floor(runif(1,min=minv,max=maxv))
  repeat {
    if (value<0){break}
    else if(value>0){break}
    else {value=floor(runif(1,min=minv,max=maxv))}
  }
  print(value)
}

Very simple. What i want to do is to make the part that restricts my function from generating zero to be just one sentence for example zero_restriction, in MY HEAD it would look like this:

customfunction=function(minv,maxv){
 value=floor(runif(1,min=minv,max=maxv))
 zero_restriction
  print(value)
}

Is this possible? Or is it too much of workaround to be worth? The point is I am going to have couple of functions each with certain restrictions, so i thought simplifying them to one word would be more convenient.

Andrew Gustar · Accepted Answer · 2017-04-25 19:08:19Z

2

If you are just using integers, one approach would be to exclude the values you don't want (such as 0) and use sample rather than runif...

customfunction <- function(minv,maxv){
  excl <- c(0) #values to exclude
  range <- seq(minv,maxv)
  range <- range[-which(range %in% excl)]
  return(sample(range,1))
}

answered Apr 25, 2017 at 19:08

Andrew Gustar

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2 Comments

Alexandros Over a year ago

Unfortunetly I will not be using only integers. I should emphasize at first post that this is only my training function, later on I want my function to take any value except 0.

Andrew Gustar Over a year ago

This approach would work with any discrete set of values - not just integers - you just need to replace the seq with something that defines the set. If you're planning to use real values then your chances of getting a zero are infinitesimal!

Sören Pannier · Accepted Answer · 2017-04-25 20:00:30Z

0

You may also consider applying a while loop e.g.

while((r <- floor(runif(1, min, max))) == 0) {  }
print(r)

This may not be the most readable solution, but it will generate new random values, as long r is set to 0, and stop doing it after it is set to a non zero value.

answered Apr 25, 2017 at 20:00

Sören Pannier

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1 Comment

Sören Pannier Over a year ago

as I just read you wont only be sampling integers. In this case this approach still works but I'd suggest a condition more like abs(x) < 1e-6 and not an exact == test

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