The function in R that can calculate how many times a digit appears in a vector

Question

So, for example, if I have a vector x <- c(11, 2354, 55, 432, 1112, 320) , the function should return a vector that indicates how many times the digits 0, 1, 2, ..., 9 have appeared in x .

For 'x', the expected counts for digits 0,1,2..9 would be c(1, 5, 4, 3, 2, 3, 0, 0, 0, 0), because, 0 only appeared once in 320, 1 appeared 2 (in 11) + 3 (in 1112) = 5 and so on.

I am trying to make function like this, but I am not really good at R. Here is what I have attempted so far:

f <- function(x){
 if(is.vector(x) & length(x) > 0) {
 z <- c(0,0,0,0,0,0,0,0,0,0)
 n <- c(nchar(x))
 for(i in range(length(x))) {
   for(d in range(n[i])) {
     for (j in range(1:10)) {
       if(x[i]%%10 == j) {
         z <- replace(z, z == z[j], z[j]+1)
       }
     }
   x <- replace(x, x == x[i], x[i]%/%10)
  }
 }return(z) 
}
}

Answer 1

Here's an alternative that uses base R and avoids for loops.

x <- c(11, 2354, 55, 432, 1112, 320)

countintegers <- function(x) {
    xpasted <- paste(x, collapse ='')
    xsplit <- strsplit(xpasted, '')
    xtable <- table(xsplit)
    empty <- table(seq(0,9)) - 1
    result <- sapply(names(empty), function(n) xtable[n] + empty[n])
    result[is.na(result)] <- 0
    as.integer(result)
}

countintegers(x)

#1 5 4 3 2 3 0 0 0 0

Answer 2

We can also use some regex for this, by pasting all the numbers into one string and then counting how many characters are removed by gsub() if a digit is replaced with "":

digitCounter <- function(x) {
   x <- paste(x, collapse = "")
   l <- vector()
   for(i in 0:9) {l[i+1] <- nchar(x) - nchar(gsub(i, "", x))}
   return(l)
}

Answer 3

I have constructed this function. This function will give how many digits of 0, 1, 2, ..., 9 appears in a vector as needed. The "main engine" of this function is the str_count() from library stringr .

library(stringr)
count_digits = function(x){
  y <- rep(0, 10)
  for(digit in 0:9){
    y[digit+1] <- sum(str_count(x,as.character(digit)))
  }
  y
}

Hope this helps.