How to calculate the entropy?

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Balkar Singh 2020-4-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/520428-how-to-calculate-the-entropy

评论： Balkar Singh 2020-5-5

采纳的回答： Ameer Hamza

How can I calculate the entropy of a sentence and selected sentence of a string. Thanks

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darova 2020-4-24

Where is MATLAB?

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采纳的回答

Ameer Hamza 2020-4-24

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/520428-how-to-calculate-the-entropy#answer_428168

在 MATLAB Online 中打开

Suppose you have a string

str = 'A quick brown fox';

1. If you have image processing toolbox, then try

ent = entropy(uint8(str))

2. Otherwise, you can also download this FEX submission: https://www.mathworks.com/matlabcentral/fileexchange/38295-compute-the-entropy-of-an-entered-text-string

ent = ComputeEntropy(str);

3. You can also write the following code which does not require any other toolbox

p = sum(str.'==unique(str))./length(str);
ent = -sum(p.*log2(p));

Same result for all three options

ent =
    3.6901

s = struct('zero', {strcat(char(8206),char(8206))},'one',{strcat(char(8206),char(8236))},'two',{strcat(char(8206),char(8237))},'three',{strcat(char(8206),char(8204))},'four',{strcat(char(8204),char(8206))},'five',{strcat(char(8204),char(8236))},'six',{strcat(char(8204),char(8237))},'seven',{strcat(char(8236),char(8236))},'eight',{strcat(char(8236),char(8204))},'nine',{strcat(char(8236),char(8237))},'dot', {strcat(char(8204),char(8204))});

final = ' ';

for i =1:size(entropy_sentences,2)

val_final='';

ent = (entropy_sentences(1,i))

input('check')

for j = 1:size(ent,2)

if(isequal(ent(1,j),0))

val = getfield(s,'zero')

input('check 0 ');

elseif(isequal(ent(1,j),1))

val = getfield(s,'one')

elseif(isequal(ent(1,j),2))

val = getfield(s,'two')

elseif(isequal(ent(1,j),3))

val = getfield(s,'three')

elseif(isequal(ent(1,j),4))

val = getfield(s,'four')

input('check 4 ');

elseif(isequal(ent(1,j),5))

val = getfield(s,'five')

elseif(isequal(ent(1,j),6))

val = getfield(s,'six')

elseif(isequal(ent(1,j),7))

val = getfield(s,'seven')

elseif(isequal(ent(1,j),8))

val = getfield(s,'eight')

elseif(isequal(ent(1,j),9))

val = getfield(s,'nine')

input('check 9');

elseif(isequal(ent(1,j),'.'))

val = getfield(s,'dot')

input('dot')

end

val_final = [val_final,val];

end

I tried this code to convert this entropy into Zero width code but its not working. There is any method to covert the entropy before embedding process.