• data.frame
  R - access data frame column using variable - Stack Overflow
  in tech > problems with boxplot colnames column-name columns double-braces r-language variable
• r - Boxplot - accessing column names with variables - Stack Overflow
  tmp1 <- 'Sepal.Width' tmp2 <- 'Species' boxplot( iris[[tmp1]] ~ iris[[tmp2]] )
  in tech > problems with boxplot column-name columns double-braces r-language variable

double-braces from all users