https://biocorecrg.github.io/CRG_RIntroduction/use-grep-and-regular-expressions-to-retrieve-columns-by-their-names.html

Build data frame

df_regex <- data.frame(expression1=1:4,
expression2=2:5,
expression3=4:7,
annotation=LETTERS[1:4],
expression4=6:3,
average_expression=c(3.25, 3.75, 4.25, 4.75),
stringsAsFactors=FALSE)

Select column names that start with “expression”

grep(pattern=”^expression”,
x=colnames(df_regex))

Select columns from df_regex if their names start with “expression”

df_regex[, grep(pattern=”^expression”, colnames(df_regex))]