Question

i'd appreciate your help on something that is currently driving me crazy. I'm processing some data regarding different characteristics with a loop & everything besides this particular function is working properly:

fun<-function(X)
   {
     Y <- numeric()
     if(max(X)== X[1]){Y<-0}else{Y=X[which.max(X)-1]}
   return(Y)
  }

so: say, I got 5 different csv.-files in my directory, which i'm refering to. in a certain row there are values, which im comparing with the expression X[which.max(X)-1]

So for instance I have got 3 values in my file:

3.5;6.4;7.1  -> the function should give me 6.4
2.8;1.6;2.3  -> the function should give me 0

... and so on.

The function itself is working, but for 5 different files I always get the same output-value. In this case I would get five time 6.4 . So it just repeats the very first output and does not actually consider the values of the second file.

I hope i explained my problem accurate and would appreciate hints and suggestions :)

the entire code:

setwd("C:\\Users")

data = list.files(pattern="*.csv", full.names= TRUE)
data
t = length(data)


    output= data.frame(Output1=NA)
    for (i in 1:t) {

      Characteristics <- read.csv(file=data[i], sep=";", nrows = 22)

      Duration = as.character (Characteristics [8,1])
      Duration = as.numeric(strsplit(Duration," ") [[1]][4])

      X = as.character(Characteristics [9:(8+Duration),1])
      X = as.numeric (X)

      fun<-function(X)
       {
         Y <- numeric()
         if(max(X)== X[1]){Y<-0}else{Y <- X[which.max(X)-1]}
       return(Y)
      }


      Output1 = Y

    output [i,1] <- Output1
    }

cheers, Olli

Answer 1

The fun has not been used properly in code. First of all, the purpose of the fun is not very clear and its not assigning any value to Y either. If purpose of the fun is to to find max value in X and assign index of it to Y. Then best option could be define the function separately.

     # define fun as separate 
      fun <- function(X)
       {
         Y <- numeric()
         if(max(X)== X[1]){Y<-0}else{Y <- X[which.max(X)-1]}
       return(Y)
      }

 #Modify for-loop as
 for (i in 1:t) { 
   Characteristics <- read.csv(file=data[i], sep=";", nrows = 22) 
   Duration = as.character (Characteristics [8,1]) 
   Duration = as.numeric(strsplit(Duration," ") [[1]][4]) 
   X = as.character(P_Char [9:(8+Duration),1]) 
   X = as.numeric (X) 

   Output1 = fun(x) 
   output [i,1] <- Output1 
}

if-else condition for multiple data files repeats output

1 个答案: