・お題：piと言えば円周率が割り当てられているように、アルファベットや月名を呼び出したい。
・Rにはもともと割り当てられている変数がある。アルファベットや月名は、以下が割り当てられているのでメモしておきたい。
> LETTERS #大文字アルファベット
[1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M" "N" "O" "P" "Q" "R" "S" "T" "U" "V" "W" "X" "Y" "Z"
> letters #小文字アルファベット
[1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" "q" "r" "s" "t" "u" "v" "w" "x" "y" "z"
> month.name #月フル
[1] "January" "February" "March" "April" "May" "June" "July" "August" "September" "October" "November" "December"
> month.abb #月略称
[1] "Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"
・ベクトルなので、revでひっくり返せる。
> rev(letters)
[1] "z" "y" "x" "w" "v" "u" "t" "s" "r" "q" "p" "o" "n" "m" "l" "k" "j" "i" "h" "g" "f" "e" "d" "c" "b" "a"
おわり
