Re: position of letters in a string

*To*: mathgroup at smc.vnet.net*Subject*: [mg53844] Re: position of letters in a string*From*: bghiggins at ucdavis.edu*Date*: Sat, 29 Jan 2005 06:02:54 -0500 (EST)*References*: <ctcr1b$24v$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Zak, Here is one way to assign a number to a letter in string based on your criterion: UnsortedUnion[x_]:=Module[{f},f[y_]:=(f[y]=Sequence[];y);f/@x] Map[MapIndexed[Rule[#1,First[#2]]&,UnsortedUnion[Characters[#]]]&,lst] {{"c" -> 1, "a" -> 2, "t" -> 3, "z" -> 4}, {"z" -> 1, "r" -> 2, "t" -> 3, "y" -> 4, "s" -> 5}} Note you cannot assign a string varable a value but if you want the string "catz" be represented by "1234" and zrtys by "12345" you can use (StringJoin[StringReplace[UnsortedUnion[Characters[#1]], MapIndexed[#1 -> ToString[First[#2]] & , UnsortedUnion[Characters[#1]]]]] & ) /@ lst {"1234", "12345"} Cheers, Brian zak wrote: > in the list of strings: > lst={"catcatz","zrzttys"} > i want some procedure to give the letters in every string a number > depending on its position and discarding the recurrent letters such > that: > first string: c=1; a=2; t=3; z=4 > second string: z=1; r=2; t=3; y=4; s=5 > zak