How to replace NA with set of values

Question

I have the following data frame:

library(dplyr)
library(tibble)


df <- tibble(
  source = c("a", "b", "c", "d", "e"),
  score = c(10, 5, NA, 3, NA ) ) 


df

It looks like this:

# A tibble: 5 x 2
  source score
  <chr>  <dbl>
1 a         10 . # current max value
2 b          5
3 c         NA
4 d          3
5 e         NA

What I want to do is to replace NA in score column with values ranging for existing max + n onwards. Where n range from 1 to total number of rows of the df

Resulting in this (hand-coded) :

  source score
  a         10
  b          5
  c         11 # obtained from 10 + 1
  d          3
  e         12 #  obtained from 10 + 2

How can I achieve that?

Answer 1

Another option :

transform(df, score = pmin(max(score, na.rm = TRUE) + 
                      cumsum(is.na(score)), score, na.rm = TRUE))

#  source score
#1      a    10
#2      b     5
#3      c    11
#4      d     3
#5      e    12

If you want to do this in dplyr

library(dplyr)
df %>% mutate(score = pmin(max(score, na.rm = TRUE) + 
                      cumsum(is.na(score)), score, na.rm = TRUE))

Answer 2

A base R solution

df$score[is.na(df$score)] <- seq(which(is.na(df$score))) + max(df$score,na.rm = TRUE)

such that

> df
# A tibble: 5 x 2
  source score
  <chr>  <dbl>
1 a         10
2 b          5
3 c         11
4 d          3
5 e         12