19130

+ signs appearing in console in R

I´m quite new at programming, and I started with R. I wanted to make a script which takes as input a matrix with the columns: time, x, y (coordenates) and then divide the time spent in each quadrant of a circular area. I have a roughly done script, but for any reason I don´t understand, when I execute the for loop in the editor, it appears all the letters red in the console with a "+" at the beginning of each line, which doesn´t let me open any other object any more when I call it.

```set.seed(20) x = matrix(rnorm(10,3,4),10,1) y = matrix (rnorm(10,3,4),10,1) time = matrix (1:10,10,1) a = cbind (time,x,y) colnames(a) = c("time","x","y") upperright = a[,2] > 0 && a[,3] > 0 upperleft = a[,2] < 0 && a[,3] > 0 lowerright = a[,2] > 0 && a[,3] < 0 lowerleft = a[,2] < 0 && a[,3] < 0 calculation <- function () { upperrightquadrant = 0 upperleftquadrant = 0 lowerrightquadrant = 0 lowerleftquadrant = 0 for (i in c(1:nrow(a))){ if (upperright) upperrightquadrant <<- sum((a[i,1]-a[i-1,1])) if (upperleft)upperleftquadrant <<- sum((a[i,1]-a[i-1,1])) if (lowerright) lowerrightquadrant <<-sum((a[i,1]-a[i-1,1])) if (lowerleft) lowerleftquadrant <<- sum((a[i,1]-a[i-1,1])) }} output = lapply (a, calculation) ```

The `+` symbols are only a way to show that the current statement is conitnuation of the previous lines's statement. That's perfectly OK. There are a couple of other problems with your program which are stopping it from producing your intended result. If I have in fact, understood what you are trying to do, I have added a possible solution at the end. First, let me suggest the edits and the reason for them:

<ol> <li>`&` should have been used instead of `&&`. `&` is the vectorized operator. So, `upperright = a[,2] > 0 & a[,3] > 0` instead of `upperright = a[,2] > 0 && a[,3] > 0`.</li> <li>You are passing a value to the function so its definition should include the parameter `calculation <- function (a)` instead of `calculation <- function ()`.</li> <li>upperright, upperleft, ... are vectors and you should check individual elements instead of the whole vector `if (upperright[i])` instead of `if (upperright)`.</li> <li>Problem with `sum((a[i,1]-a[i-1,1]))` at i==1, i-1 equals 0. If you are only counting, incrementing the count by 1 should be sufficient.</li> <li>The objects upperrightquadrant, upperleftquadrant, ... are in your function environment only. So, no need for `<<-`.</li> <li>

Finally, as you have already written the `for` loop to iterate over your matrix rowwise, no need for lapply or other similar looping functions.

Only a suggestion: Use `<-` operator for assignments instead of `=`.

</li> </ol>

Now, the corrected program:

```set.seed(20) x = matrix(rnorm(10,3,4),10,1) y = matrix (rnorm(10,3,4),10,1) time = matrix (1:10,10,1) a = cbind (time,x,y) colnames(a) = c("time","x","y") upperright = a[,2] > 0 & a[,3] > 0 upperleft = a[,2] < 0 & a[,3] > 0 lowerright = a[,2] > 0 & a[,3] < 0 lowerleft = a[,2] < 0 & a[,3] < 0 calculation <- function (a) { upperrightquadrant = 0 upperleftquadrant = 0 lowerrightquadrant = 0 lowerleftquadrant = 0 for (i in c(1:nrow(a))){ if (upperright[i]) upperrightquadrant <- upperrightquadrant + 1 if (upperleft[i]) upperleftquadrant <- upperleftquadrant + 1 if (lowerright[i]) lowerrightquadrant <- lowerrightquadrant + 1 if (lowerleft[i]) lowerleftquadrant <- lowerleftquadrant + 1 } list(upperrightquadrant = upperrightquadrant, upperleftquadrant = upperleftquadrant, lowerrightquadrant = lowerrightquadrant, lowerleftquadrant = lowerleftquadrant) } output = calculation(a) print(a) # input print(output) # output ```

EDIT

This is the edit for what you requested (Case where time instances are not contiguous). Just replace the `for` loop with this one:

``` for (i in c(1:nrow(a))){ if(i>1){ if (upperright[i]) upperrightquadrant <- upperrightquadrant + a[i, 1] - a[i-1, 1] if (upperleft[i]) upperleftquadrant <- upperleftquadrant + a[i, 1] - a[i-1, 1] if (lowerright[i]) lowerrightquadrant <- lowerrightquadrant + a[i, 1] - a[i-1, 1] if (lowerleft[i]) lowerleftquadrant <- lowerleftquadrant + a[i, 1] - a[i-1, 1] } else { if (upperright[i]) upperrightquadrant <- upperrightquadrant + a[i, 1] if (upperleft[i]) upperleftquadrant <- upperleftquadrant + a[i, 1] if (lowerright[i]) lowerrightquadrant <- lowerrightquadrant + a[i, 1] if (lowerleft[i]) lowerleftquadrant <- lowerleftquadrant + a[i, 1] } } ```

Hope, this helps.