← SASnRRenaming variables

Introduction

Renaming variables is a routine step — we might rename to meet an analysis spec, to match a standard like SDTM, or simply to make the column self-documenting.
SAS does this inside a DATA step with the rename statement (or as a dataset option).
In tidyverse we use rename() from dplyr. In base R we assign to names() directly.
This lesson renames the Age column of CLASS to age_in_years so we can compare the three approaches side by side.
After running, we should have a new dataset identical to CLASS except the Age column is now called age_in_years.

Renaming variables

SAS (Base SAS)+

data CLASS;
 infile datalines dlm='|' dsd missover;
input Name : $8. Sex : $1. Age : best32. Height : best32. Weight : best32.;
label ;
 format ;
 datalines4;
Alfred|M|14|69|112.5
Alice|F|13|56.5|84
;;;;
 run;

data renamed;
     set class;
     rename age=age_years height=height_in;
 run;

To rename variables in SAS, we write a DATA step that reads the input with SET and adds a rename statement listing old = new pairs.
rename age = age_in_years; changes the column name in the output only — the source dataset is untouched.
We can rename several columns in one statement: rename age = age_in_years height = height_cm;.
An equally common form uses the dataset option: set class (rename=(age = age_in_years));. The option form is handy when we want to rename while still in the SET step and do not want a separate rename line.
After the DATA step, the output dataset has the same rows and the same other columns, with just the Age name replaced.

R (tidyverse)+

class<-tribble(
~Name,~Sex,~Age,~Height,~Weight,
"Alfred","M",14,69,112.5,
"Alice","F",13,56.5,84,
)

 

renamed<-rename(class,Age_years=Age, Height_in=Height)

To rename columns in tidyverse, we use rename() from dplyr.
The syntax is rename(data, new_name = old_name) — note the new name goes on the left of the equals sign, opposite to SAS.
We can rename several columns in one call: rename(class, age_in_years = Age, height_cm = Height).
rename() returns a tibble with the updated column names; all other columns are unchanged.
For pattern-based renaming, dplyr offers rename_with() — for example rename_with(class, tolower) lowercases every column name at once.

Happy learning!

Search lessons

Introduction

Renaming variables