R - De/Select Columns

Use the following syntax to Select (or Deselect) specific columns in a data frame in base R:

  • Select columns by Name
df_trim <- df[c('col1', 'col2', 'col4')]
  • Select columns by Index
df_trim <- df[c(1, 2, 4)]
  • To De-Select columns by Index
df_trim <- df[-c(1, 2, 4)]
  • I have used the code below to help me discern the column names and their numbers.
col_labels <- colnames(df)

for (i in seq(1, length(col_labels))) {
  print(paste(i, col_labels[i], sep=":  "))
}

1: colname1
2: colname2