Is there a format in MATLAB to display numbers such that commas are automatically inserted into the display?

I would like to display large numbers with commas separating the digits for readability purposes. For example, I would like MATLAB to display one billion as 1,000,000,000 rather than 1000000000. How can I do this?

Answer 1

[MathWorks Support Team]

You can enhance the readability of large numbers by formatting them with commas to separate digits using the "java.text.DecimalFormat" class. See the below code for an example of this:

function numOut = addComma(numIn)
   import java.text.*
   jf=java.text.DecimalFormat; % comma for thousands, three decimal places
   numOut= char(jf.format(numIn)); % omit "char" if you want a string out
end

Then, calling the function will result in a comma separated number.

addComma(10000.12)
% 10,000.12

Answer 2

[Ted Shultz]

A simple way is to add this two line function:

function numOut = addComma(numIn)
   jf=java.text.DecimalFormat; % comma for thousands, three decimal places
   numOut= char(jf.format(numIn)); % omit "char" if you want a string out
end

Hope that helps! --ted

Answer 3

[Toshiaki Takeuchi]

Using pattern

vec = 123456789;
txt = string(vec);
pat1 = lookBehindBoundary(digitsPattern); % (?<=\d)
pat2 = asManyOfPattern(digitsPattern(3),1); % (\d{3})+
pat3 = lookAheadBoundary(pat2+lineBoundary("end")); % (?=(\d{3})+$)
pat4 = pat1+pat3; % (?<=\d)(?=(\d{3})+$)
replace(txt,pat4,",") 

ans = "123,456,789"

[Stephen23]

vec = 1234.56789;
txt = string(vec);
pat1 = lookBehindBoundary(digitsPattern); % (?<=\d)
pat2 = asManyOfPattern(digitsPattern(3),1); % (\d{3})+
pat3 = lookAheadBoundary(pat2+lineBoundary("end")); % (?=(\d{3})+$)
pat4 = pat1+pat3; % (?<=\d)(?=(\d{3})+$)
replace(txt,pat4,",") 

ans = "1234.5,679"

[Toshiaki Takeuchi]

How about this?

str = arrayfun(@(x) string(num2str(x)), (0:500:2000)');
str2 = [str;str + ".12345"]

str2 = 10×1 string array
    "0"
    "500"
    "1000"
    "1500"
    "2000"
    "0.12345"
    "500.12345"
    "1000.12345"
    "1500.12345"
    "2000.12345"

pat1 = lookBehindBoundary(digitsPattern); % (?<=\d)
pat2 = asManyOfPattern(digitsPattern(3),1); % (\d{3})+
pat3 = lookAheadBoundary(pat2+lineBoundary("end")); % (?=(\d{3})+$)
pat4 = pat1+pat3; % (?<=\d)(?=(\d{3})+$)
isDecimal = contains(str2,".");
str3 = split(str2(isDecimal),".");
str2(isDecimal) = str3(:,1);
str4 = replace(str2,pat4,",");
str4(isDecimal) = str4(isDecimal) + "." + str3(:,2)

str4 = 10×1 string array
    "0"
    "500"
    "1,000"
    "1,500"
    "2,000"
    "0.12345"
    "500.12345"
    "1,000.12345"
    "1,500.12345"
    "2,000.12345"

[Stephen23]

That seems to work much better. Note that this

str0 = arrayfun(@(x) string(num2str(x)), (0:500:2000)');

can be replaced with the much simpler and more efficient:

str1 = string(0:500:2000).';
isequal(str0,str1)

ans = logical
   1