CODEWITHSUNDEEP
r
Wombat
Wombat

Reputation: 138

R using distinct() with variable column header

Suppose I have a dataframe:

> my.df <- data.frame(uid=c(1,1,3),somevalue=c("x","y","z"))
> my.df
   uid somevalue
1    1         x
2    1         y
3    3         z

I want:

  uid somevalue
1   1         y
2   3         z

I can't use

distinct(my.df, uid, .keep_all= TRUE)

because the variable name "uid" could change. However I have the variable name stored as a string.

So I get

> iKey <- "uid"
> distinct(my.df, iKey, .keep_all= TRUE)
  uid somevalue
1   1         x
2   1         y
3   3         z
Warning message:
Trying to compute distinct() for variables not found in the data:
- `iKey`
This is an error, but only a warning is raised for compatibility reasons.
The operation will return the input unchanged.

How can I get distinct() to use the value of iKey and not take it literally?

Upvotes: 0

Views: 749

Answers (2)

andrew_reece
andrew_reece

Reputation: 21284

The tidyselect across/all_of idiom works as well:

distinct(my.df, across(all_of(iKey)), .keep_all= TRUE)

Upvotes: 1

Ronak Shah
Ronak Shah

Reputation: 389325

We can use .data pronoun :

library(dplyr)
distinct(my.df, .data[[iKey]], .keep_all= TRUE)

#  uid somevalue
#1   1         x
#2   3         z

Or convert iKey to symbol with sym and evaluate it !!

distinct(my.df, !!sym(iKey), .keep_all= TRUE)

Upvotes: 1

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