Match missing value in a data frame to another value

Question

I have a data frame with some missing group information. I want to use the value to match to where the identical value is found to assign the group.

df <- data.frame(group = c(NA, 'group1', 'group2'),
                 value = c(0.7, 0.7, 0.3))

How can I see where the value of the NA group matches to another group, and set that NA value equal to that group? Here, the NA should be 'group1'.

Does this answer your question? [replace NA value with the group value](https://stackoverflow.com/questions/23583739/replace-na-value-with-the-group-value) — Alan, Oct 05 '20 at 21:28

score 1 · Answer 1 · answered Oct 05 '20 at 21:34

1

A base R option using merge + subset

merge(df["value"],subset(df,complete.cases(df)))

which gives

  value  group
1   0.3 group2
2   0.7 group1
3   0.7 group1

answered Oct 05 '20 at 21:34

ThomasIsCoding

score 1 · Accepted Answer · answered Oct 05 '20 at 21:47

1

We can use match in base R

df$group <- with(df, na.omit(group)[match(value, unique(value))])

answered Oct 05 '20 at 21:47

akrun

2 Answers2