Replacing One Character Issue

picture = '% % %'
picture = strrep(picture,picture(1),'$')

I want to replace the 1st character with a $, but it replaces all the characters with a $. I think this is because all the characters are identical. How can I fix this without changing much of the program ?

Answer 1

[Voss]

"I want to replace the 1st character with a $"

picture = '% % %';
disp(picture)

% % %

picture(1) = '$';
disp(picture)

$ % %

Note that that replaces the first character of picture with "$" regardless of what that character was (i.e., it does not replace the first character that's "%").

picture = 'c% % %';
disp(picture)

c% % %

picture(1) = '$';
disp(picture)

$% % %

[Voss]

If you actually want to replace the first character that's "%" with "$", then:

picture = '% % %';
disp(picture)

% % %

idx = find(picture == '%', 1);
if ~isempty(idx)
    picture(idx) = '$';
end
disp(picture)

$ % %

picture = 'c% % %';
disp(picture)

c% % %

idx = find(picture == '%', 1);
if ~isempty(idx)
    picture(idx) = '$';
end
disp(picture)

c$ % %

[Kimi Raikonnen]

Thanks for your help. I don't understand the difference between the 2. Is it that the 1st is more efficient since it replaces whatever the 1st character is with a $ ?

[Kimi Raikonnen]

Also, does disp(picture) convert picture from a string into an array ? If so, can I do this keeping it as a string ?

[Kimi Raikonnen]

Actually, disp is just an alternative to fprint isn't it ?

[Voss]

The difference is that one replaces the first character and one replaces the first '%'.

disp does no conversion.

disp displays to the command line, yes.