Unable to open .csv file in R ,whose file name is obtained by concatenating a string with a variable

Question

airprobread <- function(id) {
  fi <- list()
  for (i in id) {
    if(i < 10) {
      fi[[i]] <- read.csv(file = paste("00",i,".csv",sep=""))
    } else 
    if((i >= 10) & (i < 100)) {
      fi[[i]] <- read.csv(file=paste("0",i,".csv",sep=""))
    } else 
    if (i >= 100) {
      fi[[i]] <- read.csv(file=paste(i,".csv",sep=""))
    }          
  }

  for (j in id) {
    print(fi[[j]]) 
  }
}

I am unable to understand why the concatenation is not happening in the case of paste() function
Files from 001.csv to 009.csv and 010.csv to 099.csv not opening. Gives comments like:

In file(file, "rt") : cannot open file '2.csv': No such file or directory

In file(file, "rt") : cannot open file '34.csv': No such file or directory

but it works for values above 100.csv (file opens for 315.csv)

I'm here so pardon me for the formatting.

Think it should be `else if (i >= 100)` instead of just `else ( 1 >= 100)`. After that correction the strings are produced correctly. — koekenbakker, Jan 20 '17 at 08:42

score 1 · Answer 1 · answered Jan 20 '17 at 08:56

1

You could use sprintf and avoid the if-clause to add the leading zeroes:

fi[[i]] <- read.csv(file=sprintf("%03d.csv", i))

answered Jan 20 '17 at 08:56

mpjdem

1,504
9
14

score 0 · Answer 2 · answered Jan 20 '17 at 08:54

Would this be useful for you?

> paste0(sprintf("%03d",c(1,10,99,100,999,1000)), ".csv")
[1] "001.csv"  "010.csv"  "099.csv"  "100.csv"  "999.csv"  "1000.csv"

mpjdem's answer is better

> sprintf("%03d.csv",c(1,10,99,100,999,1000))
[1] "001.csv"  "010.csv"  "099.csv"  "100.csv"  "999.csv"  "1000.csv"

Unable to open .csv file in R ,whose file name is obtained by concatenating a string with a variable

2 Answers2