'Count repeats in a list and store them as a multiple

I have a list, which looks like this (the ID is the name of each element in the list and the scores are the values). enter image description here

The problem is some of the elements contain duplicate values. For example: for ID = 8, the scores are: 1, 1, 2, 4.

I want to be able to count if there are any repeats and store the number of repeats. In this case: 1x2, 2, 4.

I have tried:

str_count(patient.variants[[8]], "1")

But this just returns: 1, 1, 0, 0.

Data for Example
list("1" = c("1", "2", "2"), "2" = c("1", "1", "2", "3"), "3" = c("1", "1", "2", "2"))
rlist


Solution 1:[1]

You can try

lapply(lst, \(x) {
  tab <- table(x)
  unname(ifelse(tab > 1, paste(names(tab), tab, sep = "x"), names(tab)))
})

# $`1`
# [1] "1"   "2x2"
# 
# $`2`
# [1] "1x2" "2"   "3"  
# 
# $`3`
# [1] "1x2" "2x2"
Data
lst <- list("1" = c("1", "2", "2"),
            "2" = c("1", "1", "2", "3"),
            "3" = c("1", "1", "2", "2"))

Solution 2:[2]

An option with tapply

lapply(lst1, \(x) unname(tapply(x, x, FUN = function(x) 
   if(length(x) > 1) paste(x[1], length(x), sep = "X") else x)))
$`1`
[1] "1"   "2X2"

$`2`
[1] "1X2" "2"   "3"  

$`3`
[1] "1X2" "2X2"

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Darren Tsai
Solution 2 akrun

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