[R] How to get a degree sign into a lattice factor level?

[Martin Maechler]

       {needing several trials to get this answer through the R-help filters!
        please apologize, Sonam! -- MM}

>>>>> "Sonam" == Sonam Lodro <kagyukid at yahoo.com>
>>>>>     on Mon, 11 Nov 2002 17:04:57 -0800 (PST) writes:

    Sonam> I notice that expressions can be used in legends, but
    Sonam> as far as I can tell, cannot be used as levels for
    Sonam> factors.  I'd like to be able to do something like
    Sonam> that so that the levels printed in a lattice plot
    Sonam> show the degree character.

    Sonam> In Splus, I used to use element [203] (if I remember
    Sonam> correctly) of a vector called All.ASCII which could
    Sonam> be pasted with text to produce the effect I require.

    Sonam> What is a good way to achieve the same in R?

R uses iso-8859-1 (aka "iso-latin1") per default.
Hence the following works ``automatically''

  > f4 <- gl(4, 3, labels = paste(10*(0:3),"°", sep=""))
  > f4
   [1] 0°  0°  0°  10° 10° 10° 20° 20° 20° 30° 30° 30°
  Levels: 0° 10° 20° 30°

Now, how do you enter the `°' character ?
I use Emacs and the sequence
`C-x 8 * o' 

(In Emacs, type  `` C-x 8 C-h ''  to get a list of all
 ``international characters'' you can get with C-x 8 prefixes.
 Locally we also use "A-" ("Alt" != Meta) key for entering
 things like these; for us particularly the µäöü¢© .. are simple
 Alt-key strokes)

The All.ASCII[] vector you found in S-plus actually comes from
Statlib/S-news and was contributed by myself about 10 years ago.
Here is one way to define it  {not the shortest at all, but
easiest to understand} :

All.ASCII <-
  c("\000", "\001", "\002", "\003", "\004", "\005", "\006", "\007", 
    "\b", "\t", "\n",
	"\013", "\014", "\r", "\016", "\017", "\020", "\021", "\022", "\023",
	"\024", "\025", "\026", "\027", "\030", "\031", "\032", "\033", "\034",
	"\035", "\036", "\037", " ", "!", "\"", "#", "$", "%", "&", "'", "(",
	")", "*", "+", ",", "-", ".", "/", "0", "1", "2", "3", "4", "5", "6",
	"7", "8", "9", ":", ";", "<", "=", ">", "?", "@", 
	LETTERS, "[", "\\", "]", "^", "_", "`",
	letters, "{", "|", "}", "~", 
	"\177", "\200", "\201", "\202", "\203", "\204", "\205", 
	"\206", "\207", "\210", "\211", "\212", "\213", "\214", "\215", "\216",
	"\217", "\220", "\221", "\222", "\223", "\224", "\225", "\226", "\227",
	"\230", "\231", "\232", "\233", "\234", "\235", "\236", "\237", "\240",
	"\241", "\242", "\243", "\244", "\245", "\246", "\247", "\250", "\251",
	"\252", "\253", "\254", "\255", "\256", "\257", "\260", "\261", "\262",
	"\263", "\264", "\265", "\266", "\267", "\270", "\271", "\272", "\273",
	"\274", "\275", "\276", "\277", "\300", "\301", "\302", "\303", "\304",
	"\305", "\306", "\307", "\310", "\311", "\312", "\313", "\314", "\315",
	"\316", "\317", "\320", "\321", "\322", "\323", "\324", "\325", "\326",
	"\327", "\330", "\331", "\332", "\333", "\334", "\335", "\336", "\337",
	"\340", "\341", "\342", "\343", "\344", "\345", "\346", "\347", "\350",
	"\351", "\352", "\353", "\354", "\355", "\356", "\357", "\360", "\361",
	"\362", "\363", "\364", "\365", "\366", "\367", "\370", "\371", "\372",
	"\373", "\374", "\375", "\376", "\377")

-----------
and here are ways to use it

> which(All.ASCII == "°")
[1] 177

> All.ASCII[1:128] # the `proper' ASCIIs
  [1] ""   "
"  ""  ""  ""  ""  ""  "\a" "\b" "\t" "\n"
 [12] "\v" "\f" "\r" ""  ""  ""  ""  ""  ""  ""  "" 
 [23] ""  ""  ""  ""  ""  ""  "
"  "
"  "
"  ""  " " 
 [34] "!"  "\"" "#"  "$"  "%"  "&"  "'"  "("  ")"  "*"  "+" 
 [45] ","  "-"  "."  "/"  "0"  "1"  "2"  "3"  "4"  "5"  "6" 
 [56] "7"  "8"  "9"  ":"  ";"  "<"  "="  ">"  "?"  "@"  "A" 
 [67] "B"  "C"  "D"  "E"  "F"  "G"  "H"  "I"  "J"  "K"  "L" 
 [78] "M"  "N"  "O"  "P"  "Q"  "R"  "S"  "T"  "U"  "V"  "W" 
 [89] "X"  "Y"  "Z"  "["  "\\" "]"  "^"  "_"  "`"  "a"  "b" 
[100] "c"  "d"  "e"  "f"  "g"  "h"  "i"  "j"  "k"  "l"  "m" 
[111] "n"  "o"  "p"  "q"  "r"  "s"  "t"  "u"  "v"  "w"  "x" 
[122] "y"  "z"  "{"  "|"  "}"  "~"  "" 

Martin Maechler <maechler at stat.math.ethz.ch>	http://stat.ethz.ch/~maechler/
Seminar fuer Statistik, ETH-Zentrum  LEO C16	Leonhardstr. 27
ETH (Federal Inst. Technology)	8092 Zurich	SWITZERLAND
phone: x-41-1-632-3408		fax: ...-1228			<><

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