--- delete(str[, str2[,  ... ]])
--- delete!(str[, str2[,  ... ]])

    ʸ󤫤 str ˴ޤޤʸޤ

    str η tr(1) [manual page] ƱǤĤޤꡢ
    `a-c'  a  c ̣"^0-9" Τ褦
    ʸƬ `^' ξϻʸʳ̣ޤ

    `-' ʸξüˤʤˤϰϻΰ̣ˤʤޤ
    Ʊͤˡ`^' ⤽θ̤ʸƬˤȤǤޤ
    `-', `^', `\' ϥХåå(`\')ˤ
    ꥨפ뤳ȤǤޤ

    ʣꤷϡ٤Ƥΰѽ̣ޤ

        p "123456789".delete("2-8", "^4-6")  #=> "14569"
        p "123456789".delete("2378")         #=> "14569"

    delete ѹʸ֤ޤ
    delete!  self ѹ֤ޤѹ
    ʤä nil ֤ޤ

