% string functions
help strfun

% opening a file
help fopen

% reading a line of a file
help fgetl

% reading in file one line at a time. 
fid = fopen('/Users/tlberg/Desktop/teaching/Spring_10/demos/textProc/text.txt','r');
while 1
	tline = fgetl(fid);
	if ~ischar(tline), break, end
	tline
end
fclose(fid);

% what if we want to split each line into individual words
help strtok
fid = fopen('/Users/tlberg/Desktop/teaching/Spring_10/demos/textProc/text.txt','r');
count=0;
while 1
	tline = fgetl(fid);
	if ~ischar(tline), break, end
	r = tline;
	while ~isempty(r)
		[t,r] = strtok(r);
		t
	end
end

% now let's find which of those words are the word 'text'
fid = fopen('/Users/tlberg/Desktop/teaching/Spring_10/demos/textProc/text.txt','r');
count=0;
while 1
	tline = fgetl(fid);
	if ~ischar(tline), break, end
	r = tline;
	while ~isempty(r)
		[t,r] = strtok(r);
		if strcmp(t,'text')
			count=count+1;
		end
	end
end
fclose(fid);
count

% find all occurences of the word text and don't care about capitalization
help strcmpi
fid = fopen('/Users/tlberg/Desktop/teaching/Spring_10/demos/textProc/text.txt','r');
count=0;
while 1
	tline = fgetl(fid);
	if ~ischar(tline), break, end
	r = tline;
	while ~isempty(r)
		[t,r] = strtok(r);
		if strcmpi(t,'text')
			count=count+1;
		end
	end
end
fclose(fid);
count

% find all occurences of the substring text even if it's part of another word
fid = fopen('/Users/tlberg/Desktop/teaching/Spring_10/demos/textProc/text.txt','r');
count=0;
while 1
	tline = fgetl(fid);
	if ~ischar(tline), break, end
	a = strfind(tline,'text');
	if ~isempty(a)
		count=count+length(a);
	end
end
fclose(fid);
count

% what if we want to read each line into a cell array for later processing
fid = fopen('/Users/tlberg/Desktop/teaching/Spring_10/demos/textProc/text.txt','r');
lines = [];
while 1
	tline = fgetl(fid);
	if ~ischar(tline), break, end
	lines{end+1} = tline;
end
fclose(fid);
length(lines)

% what if we want to read each non-empty line into a cell array
fid = fopen('/Users/tlberg/Desktop/teaching/Spring_10/demos/textProc/text.txt','r');
lines = [];
while 1
	tline = fgetl(fid);
	if ~ischar(tline), break, end
	if ~isempty(tline)
		lines{end+1} = tline;
	end
end
fclose(fid);

% show lines in array
lines{1}
lines{2}
lines{3}
length(lines)

% find a particular string in your array
inds = strcmp(lines,'For texting language, see SMS language.');
inds
ind = find(inds);
ind
lines{ind};

% can directly index into strings
a = lines{8};
a
a(4:20) 
% character 4 through end of string
a(4:end)

b = lines{5};
b

% can easily concatenate strings
c = [a b];
c

% can set substrings to new strings easily
b
b(4:11+3) = ['hello world'];

a = 'LSkJLkJ'
a 
lower(a)
upper(a)


help strrep
b = strrep(b,'hello','goodbye');
b