MATLAB: Replacing Occurrences of String

replace string

(Ajay deleted this so I (MF) am restoring it)
How do I replace every instance of 'str1' in a input sentence? My function (ReplaceStrAll) should return the intact input sentence as its output, if it cannot find any occurrence of str1 in the input sentence.
This is the code I wrote:
function output_sentence = ReplaceStrAll(input_sentence, str1, str2) 
str1_index = strfind(input_sentence,str1); 
output_sentence = [input_sentence(1:str1_index(1)-1),str2,... input_sentence( str1_index(1)+length(str1):length(input_sentence) )];
what is wrong with it? I already got verification that I'm on the right path and I just need to make a few adjustments, but what am I messing up in the code?

Best Answer

please try this is code:
out = input_sentence;
ii = strfind(out,str1)
if ~isempty(ii)
    for ii = ii
        out = [out(1:ii-1),str2,out(ii+numel(str1):end)];
    end
end
or
out = input_sentence;
[i1,i2] = regexp(out,str1);
if ~isempty(i1)
    for ii = 1:numel(i1)
        out = [out(1:i1(ii)-1),str2,out(i2(ii)+1:end)];
    end
end
or
out = regexprep(input_sentence,str1,str2);
or
out = strrep(input_sentence,str1,str2);
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