# HG changeset patch # User jwe # Date 1162579146 0 # Node ID 4da9f63d5237a9ec9791fb2d9536f52da21308f7 # Parent c5874b47d571f616e5b6ac77d953a5163c77a6e0 [project @ 2006-11-03 18:39:06 by jwe] diff --git a/scripts/ChangeLog b/scripts/ChangeLog --- a/scripts/ChangeLog +++ b/scripts/ChangeLog @@ -1,5 +1,8 @@ 2006-11-03 Bill Denney + * strings/index.m: New arg, direction. Simplify and speed up. + * strings/rindex.m: Implement using index (..., "last"); + * scripts/blanks.m, scripts/strcat.m: Simplify. Add tests. 2006-11-01 Bill Denney diff --git a/scripts/strings/index.m b/scripts/strings/index.m --- a/scripts/strings/index.m +++ b/scripts/strings/index.m @@ -1,4 +1,4 @@ -## Copyright (C) 1996 Kurt Hornik +## Copyright (C) 1996, 2006 Kurt Hornik ## ## This file is part of Octave. ## @@ -19,6 +19,7 @@ ## -*- texinfo -*- ## @deftypefn {Function File} {} index (@var{s}, @var{t}) +## @deftypefnx {Function File} {} index (@var{s}, @var{t}, @var{direction}) ## Return the position of the first occurrence of the string @var{t} in the ## string @var{s}, or 0 if no occurrence is found. For example, ## @@ -27,74 +28,103 @@ ## @result{} 4 ## @end example ## -## @strong{Caution:} This function does not work for arrays of strings. +## If @var{direction} is @samp{"first"}, return the first element found. +## If @var{direction} is @samp{"last"}, return the last element found. +## The @code{rindex} function is equivalent to @code{index} with +## @var{direction} set to @samp{"last"}. +## +## @strong{Caution:} This function does not work for arrays of +## character strings. +## @seealso{find, rindex} ## @end deftypefn ## Author: Kurt Hornik ## Adapted-By: jwe -function n = index (s, t) +function n = index (s, t, direction) ## This is patterned after the AWK function of the same name. - if (nargin != 2) + if (nargin < 2 || nargin > 3) print_usage (); + elseif (nargin < 3) + direction = "first"; endif - - if (!ischar (s) || !ischar (t) || all (size (s) > 1) || all (size (t) > 1) ) - error ("index: expecting string arguments"); + direction = lower (direction); + + if (! (ischar (s) && ischar (t) && isvector (s) && isvector (t))) + error ("index: expecting character string arguments"); + elseif (! strcmp (direction, {"first", "last"})) + error ("index: direction must be either \"first\" or \"last\""); endif l_s = length (s); l_t = length (t); - - if ( l_s == 0 || l_s < l_t ) + + n = 0; + if (l_s == 0 || l_s < l_t) ## zero length source, or target longer than source + ## return 0 v = []; - - elseif ( l_t == 0 ) + + elseif (l_t == 0) ## zero length target: return first v = 1; - - elseif ( l_t == 1 ) + + elseif (l_t == 1) ## length one target: simple find - v = find (s==t); - - elseif ( l_t == 2 ) + v = find (s==t, 1, direction); + + elseif (l_t == 2) ## length two target: find first at i and second at i+1 - v = find (s (1 : l_s-1) == t (1) & s (2 : l_s) == t (2)); - + v = find (s (1:l_s-1) == t(1) & s(2:l_s) == t(2), 1, direction); + else ## length three or more: match the first three by find then go through ## the much smaller list to determine which of them are real matches limit = l_s - l_t + 1; - v = find (s (1 : limit) == t(1) & s (2 : limit+1) == t (2) - & s (3 : limit+2) == t(3) ); - endif - - if (l_t > 3) - - ## force strings to be both row vectors or both column vectors - if (all (size (s) != size (t))) - t = t.'; + v = find (s (1:limit) == t(1) + & s (2:limit+1) == t(2) + & s (3:limit+2) == t(3)); + if (strcmp (direction, "last")) + v = v(length(v):-1:1); endif - - ## search index vector for a match - ind = 0 : l_t - 1; - n = 0; # return 0 if loop terminates without finding any match - for idx = 1:length(v) - if (s (v(idx) + ind) == t) - n = v(idx); - break; + + if (l_t > 3) + + ## force strings to be both row vectors or both column vectors + if (all (size (s) != size (t))) + t = t.'; endif - endfor - elseif (length(v) > 0) - n = v(1); - - else - n = 0; + ## search index vector for a match + ind = 0:l_t-1; + ## return 0 if loop terminates without finding any match + for idx = 1:length(v) + if (s (v(idx) + ind) == t) + n = v(idx); + break; + endif + endfor + endif endif + if (n == 0 && ! isempty (v)) + ## return the first found if n is not already set and v is not empty + n = v(1); + endif + endfunction + +## Test the function out +%!assert(index("astringbstringcstring", "s"), 2) +%!assert(index("astringbstringcstring", "st"), 2) +%!assert(index("astringbstringcstring", "str"), 2) +%!assert(index("astringbstringcstring", "string"), 2) + +## test everything out in reverse +%!assert(index("astringbstringcstring", "s", "last"), 16) +%!assert(index("astringbstringcstring", "st", "last"), 16) +%!assert(index("astringbstringcstring", "str", "last"), 16) +%!assert(index("astringbstringcstring", "string", "last"), 16) diff --git a/scripts/strings/rindex.m b/scripts/strings/rindex.m --- a/scripts/strings/rindex.m +++ b/scripts/strings/rindex.m @@ -1,4 +1,4 @@ -## Copyright (C) 1996 Kurt Hornik +## Copyright (C) 1996, 2006 Kurt Hornik ## ## This file is part of Octave. ## @@ -19,15 +19,18 @@ ## -*- texinfo -*- ## @deftypefn {Function File} {} rindex (@var{s}, @var{t}) -## Return the position of the last occurrence of the string @var{t} in the -## string @var{s}, or 0 if no occurrence is found. For example, +## Return the position of the last occurrence of the character string +## @var{t} in the character string @var{s}, or 0 if no occurrence is +## found. For example, ## ## @example ## rindex ("Teststring", "t") ## @result{} 6 ## @end example ## -## @strong{Caution:} This function does not work for arrays of strings. +## @strong{Caution:} This function does not work for arrays of +## character strings. +## @seealso{find, index} ## @end deftypefn ## Author: Kurt Hornik @@ -41,60 +44,6 @@ print_usage (); endif - if (!ischar (s) || !ischar (t) || all (size (s) > 1) || all (size (t) > 1) ) - error ("rindex: expecting string arguments"); - endif - - l_s = length (s); - l_t = length (t); - - if ( l_s == 0 || l_s < l_t ) - ## zero length source, or target longer than source - v = []; - - elseif ( l_t == 0 ) - ## zero length target: return last - v = l_s; - - elseif ( l_t == 1 ) - ## length one target: simple find - v = find (s==t); - - elseif ( l_t == 2 ) - ## length two target: find first at i and second at i+1 - v = find (s (1 : l_s-1) == t (1) & s (2 : l_s) == t (2)); - - else - ## length three or more: match the first three by find then go through - ## the much smaller list to determine which of them are real matches - limit = l_s - l_t + 1; - v = find (s (1 : limit) == t(1) & s (2 : limit+1) == t (2) - & s (3 : limit+2) == t(3) ); - endif - - if (l_t > 3) - - ## force strings to be both row vectors or both column vectors - if (all (size (s) != size (t))) - t = t.'; - endif - - ## search index vector for a match - ind = 0 : l_t - 1; - n = 0; # return 0 if loop terminates without finding any match - for idx = length(v):-1:1 - if (s (v(idx) + ind) == t) - n = v(idx); - break; - endif - endfor - - elseif (length(v) > 0) - n = v(length(v)); - - else - n = 0; - - endif + n = index (s, t, "last"); endfunction