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comparison scripts/strings/findstr.m @ 2275:38fea6d34daf

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[project @ 1996-05-24 04:06:52 by jwe]
author jwe
date Fri, 24 May 1996 04:08:52 +0000
parents e97fba45f0a3
children 6dedd4e0a82f
comparison
equal deleted inserted replaced
2274:9750746d7da5 2275:38fea6d34daf
14 # 14 #
15 # You should have received a copy of the GNU General Public License 15 # You should have received a copy of the GNU General Public License
16 # along with Octave; see the file COPYING. If not, write to the Free 16 # along with Octave; see the file COPYING. If not, write to the Free
17 # Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 17 # Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 18
19 function v = findstr (s, t) 19 function v = findstr (s, t, overlap)
20 20
21 # usage: findstr (s, t) 21 # usage: findstr (s, t [, overlap])
22 # 22 #
23 # Returns the vector of all positions in the longer of the two strings 23 # Returns the vector of all positions in the longer of the two strings
24 # S and T where an occurence of the shorter of the two starts. 24 # S and T where an occurence of the shorter of the two starts.
25 25 #
26 # If the optional argument OVERLAP is nonzero, the returned vector
27 # can include overlapping positions (this is the default).
28 #
29 # For example,
30 #
31 # findstr ("abababa", "aba") => [1, 3, 5]
32 # findstr ("abababa", "aba", 0) => [1, 5]
33
26 # Original version by Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at>. 34 # Original version by Kurt Hornik <Kurt.Hornik@ci.tuwien.ac.at>.
27 35
28 if (nargin != 2) 36 if (nargin < 2 || nargin > 3)
29 usage ("findstr (s, t)"); 37 usage ("findstr (s, t [, overlap])");
38 endif
39
40 if (nargin == 2)
41 overlap = 1;
30 endif 42 endif
31 43
32 if (isstr (s) && isstr (t)) 44 if (isstr (s) && isstr (t))
33 45
34 # Make S be the longer string. 46 # Make S be the longer string.
40 endif 52 endif
41 53
42 s = toascii (s); 54 s = toascii (s);
43 t = toascii (t); 55 t = toascii (t);
44 56
45 ind = 1 : length (t); 57 l_t = length (t);
46 limit = length (s) - length (t) + 1; 58
59 ind = 1 : l_t;
60 limit = length (s) - l_t + 1;
47 v = zeros (1, limit); 61 v = zeros (1, limit);
48 i = 0; 62 i = 0;
49 63
50 for k = 1 : limit 64 k = 1;
65 while (k <= limit)
51 if (s (ind + k - 1) == t) 66 if (s (ind + k - 1) == t)
52 v (++i) = k; 67 v (++i) = k;
68 if (! overlap)
69 k = k + l_t - 1;
70 endif
53 endif 71 endif
54 endfor 72 k++;
73 endwhile
55 74
56 if (i > 0) 75 if (i > 0)
57 v = v (1:i); 76 v = v (1:i);
58 else 77 else
59 v = []; 78 v = [];
60 endif 79 endif
61 80
62 else 81 else
63 error ("findstr: both arguments must be strings"); 82 error ("findstr: expecting first two arguments to be strings");
64 endif 83 endif
65 84
66 endfunction 85 endfunction