Topics

SAS programming tasks mapped to R.

Basics

• Mutate create or change columns
• Select and rename keep, drop, and rename columns
• Filter keep rows that match a condition
• If else and case when conditional column values
• Coalesce prefer one value, fall back to another

Text

• Substrings extract part of a character value

Dates

• Study day date subtraction for --DY
• Partial dates impute year-only or year-month to a full date

Combining Data

• Joins combining tables
• Bind rows stack tables on top of each other

Derivations

• Sequence numbers --SEQ within a subject
• Last observation before exposure --LOBXFL flags