← SASnRConvert all the variable names to uppercase

Introduction

In clinical programming, variable names are often ALL CAPS to match SDTM and ADaM conventions (USUBJID, STUDYID, ADSL, and so on).
When we import data from CSV, Excel or an external vendor, the names rarely arrive uppercase — we have to force them ourselves.
SAS gives us the options validvarname=upcase; global setting that makes every variable name uppercase from the point it is set.
R has no global option like this, but rename_with(toupper) (tidyverse) or a direct assignment to names() (base R) does the same job at the dataset level.
This lesson shows how to normalise all column names to uppercase after reading in a dataset.
After running, every column name in the output is ALL CAPS.

Convert all the variable names to uppercase

SAS (Base SAS)+

options validvarname=upcase;

data class;
    input name $ sex $ age height weight;
    datalines;
Alfred M 14 69 112.5
Alice F 13 56.5 84
;
run;

To force SAS to uppercase every variable name, we set options validvarname=upcase; before the DATA step.
validvarname controls how SAS treats variable names it creates or reads. The upcase value means “if a name arrives in mixed case, store it in upper case”.
After the option is set, any dataset we create (including via proc import or a DATA step reading external files) has uppercase variable names by default.
The option is global — it stays in force for the rest of the session unless we reset it. For a one-off, wrap it with options validvarname=v7; at the end to restore default behaviour.
After running, a proc contents confirms every variable name is uppercase.

R (tidyverse)+

library(tidyverse)

class <- tribble(
~name, ~sex, ~age, ~height, ~weight,
"Alfred", "M", 14, 69, 112.5,
"Alice", "F", 13, 56.5, 84
)

 
#Convert column names to uppercase

class_upper <- class %>%
rename_with(toupper)

In tidyverse, we uppercase every column name with a single call to rename_with().
rename_with(data, toupper) applies the toupper function to each column name and replaces the old name with the result.
This is the tidyverse analogue of the SAS validvarname=upcase option, applied per-dataset rather than globally.
The same helper works for other transformations: tolower for lower case, make.names for valid R identifiers, or a custom function for complex renames.
After running, names(class) prints every column name in upper case.

Happy learning!

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Introduction

Convert all the variable names to uppercase