Replace letter with dot

Does anybody know how to replace first letter as well as same subsequent letters of a word with dot in a string?

For instance:

'MOMENT AND INITIALIZATION'

i need: '.O.ENT AND .N.T.AL.ZAT.ON'

To note, I need all white spaces to be saved as they are.

Answer 1

[Star Strider]

Try this:

str = 'MOMENT AND   INITIALIZATION';
newstr = str;
old = {'M','I'}';
for k = 1:numel(old)
    newstr = strrep(newstr, old(k),{'.'});
end
newstr

producing:

newstr =

  1×1 cell array

    {'.O.ENT AND   .N.T.AL.ZAT.ON'}

[Dos Zhu]

what if I prompt user to enter words?

[Star Strider]

First, I would use the inputdlg function for tthat.

Second, the strrep function is case-sensitive, so you would need to account for that. It would likely be easiest to use the upper function to convert the input string to all uppercase, then do the replacements.