# How can I display numbers in scientific notation but in magnitudes of 3 and to 3 significant digits?

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Allen on 1 Feb 2023
Commented: John D'Errico on 11 Feb 2023
I am trying to display rounded values <double> in a uitable and would like do so concisely. Using scientific notation is great for this, but I would like to have the scientific notation display only as powers divisible by 3. Additionally, the I would also like to display 3 significant digits.
For example:
1 = 1
10 = 10
100 = 100
1000 = 1.00e3
10000 = 10.0e3
100000 = 100e3
1000000 = 1.00e6
John D'Errico on 11 Feb 2023
sprintf SHOULD offer this as one of the options.

Dongyue on 7 Feb 2023
classdef ScientificNotation
properties(Access = private)
sign;
body;
digs;
num;
end
methods
function s = ScientificNotation(num)
s.num = num;
if num< 0
s.sign = '-';
else
s.sign = '';
end
num = double(abs(num));
if num<1000
s.body = "";
s.digs = string(num);
else
tmp = 0;
while num >= 1000
tmp = tmp +3;
num = num/1000;
end
s.body = "e"+string(tmp);
str = string(round(num,3,'significant'));
if strlength(str) == 1
str = str+".00";
elseif strlength(str) == 2
str = str+".0";
elseif strlength(str) == 3
if contains(str,'.')
str = str+"0";
end
end
s.digs = str;
end
end
function disp(s)
fprintf(string(s.num)+" = %s%s%s\n",[ s.sign, s.digs,s.body]);
end
end
end
Allen on 11 Feb 2023
Thank you for your response, but unfortunately I am trying to directly format doubles and not convert to text. I always like seeing new uses for classdefs.