changing exponential value into float

I normalized 'area' data between zero and one. Then I write that values into xl sheet. But many values are exponential. I want to change that exponential values to float type. Please somebody help.

This is my code:

max_Ar=max(Ar);
min_Ar=min(Ar);
range=(max_Ar-min_Ar)+ eps(max_Ar-min_Ar);

for i=1:100
Area(i)=(Ar(i)-(min_Ar - eps(max_Ar-min_Ar)))/range;
ex = 10^(3-floor(log10(Area(i))));
Area(i)= round(Area(i) * ex) / ex;
end
xlswrite('Tomato_Yellow_Leaf_Curl_Virus.xlsx',Ar(:)) 
xlswrite('Tomato_Yellow_Leaf_Curl_Virus1.xlsx',Area(:))

[Walter Roberson]

If for example one entry was 1.23e-8 then what float would you want? Do you want to just change it to have as many leading or trailing zeroes as needed, or do you want to round numbers with abs() value less than something to be 0?

[Sajitha K.N.]

No I want values between 0 and 1.

[Walter Roberson]

You did not answer my questions.

[Sajitha K.N.]

I want to just change it to have as many leading or trailing zeroes as needed.

Answer 1

[Subhadeep Koley]

Hi Sajitha, Try the code below.

clc;
max_Ar = max(Ar);
min_Ar = min(Ar);
range = (max_Ar - min_Ar) + eps(max_Ar - min_Ar);
for i = 1:100
    Area(i) = (Ar(i) - (min_Ar - eps(max_Ar-min_Ar))) / range;
    ex = 10^(3-floor(log10(Area(i))));
    Area(i) = round(Area(i) * ex) / ex;
    
    Area(i) = str2double(sprintf('%f', Area(i)));
    Ar(i) = str2double(sprintf('%f', Ar(i)));
end
xlswrite('Tomato_Yellow_Leaf_Curl_Virus.xlsx', double(Ar(:)));
xlswrite('Tomato_Yellow_Leaf_Curl_Virus1.xlsx', double(Area(:)));

Answer 2

[Walter Roberson]

dlmwrite with a precision of '%.1074f' should handle all of the cases.

Possibly with the processing you are doing you might be able to use a considerably smaller number than 1074. 1074 is needed for eps(realmin)

[Sajitha K.N.]

My dataset is very big one. Is this code slow down the process?

[Walter Roberson]

Yes. Conversion of binary to characters is done in software, not in hardware. The more digits you convert, the more time it takes the software.

File i/o time mostly depends on the number of full blocks of data to be written; when you write more characters then it is going to take more time.