how to round number in table to two digit number

I have a table as an output in my code but all of numbers have 5 digit numbers after decimal. How I should change it to two decimals for whole of the table? (like 0.38878 to 0.39)

this is last part of my code

f=(x1(1:21)*AA)';
u=[x1(22:end) 0 0 0]';
Data=table(f,u)

     f         u  
      ______    _____

      4.4532    4e-07
      9.4421    4e-07
      9.1827    4e-07
      2.3218    4e-07
      2.1314    4e-07
      3.7149    4e-07
      5.7272    4e-07
      7.6894    4e-07
      1.4933    4e-07
      13.726    4e-07

[dpb]

'Pends on how you're outputting to where...show us the code that produces the table.

[Maryam Abdirad]

this is last part of my code

f=(x1(1:21)*AA)';
u=[x1(22:end) 0 0 0]';
Data=table(f,u)

and this is my answer
Data = 

        f         u  
      ______    _____

      4.4532    4e-07
      9.4421    4e-07
      9.1827    4e-07
      2.3218    4e-07
      2.1314    4e-07
      3.7149    4e-07
      5.7272    4e-07
      7.6894    4e-07
      1.4933    4e-07
      13.726    4e-07
      9.3519    4e-07
      6.3301    4e-07
       2.918    4e-07
       4.478    4e-07
      2.0276    4e-07
      2.6431    4e-07
      4.6811    4e-07
           5        0
          10        0
           5        0

[Jonathan]

did you ever get an asnwer to this? ive read below but cannot find the solution. i know of fprintf(.... buti dont know how to format the inside of the brackets to show whjat i need (2dp)

[Walter Roberson]

fprintf('%10.2f %10.2f\n', [f(:).'; u(:).']);

Answer 1

[Walter Roberson]

Data = table( round(f,2), round(u,2))

However, you need to distinguish between what is stored and how it is displayed. MATLAB uses IEEE 754 Double Precision for values like 0.38878 and those are represented by 53 bits of precision in binary. It is not possible to exactly represent 1/10 in binary, so even though you might have rounded to 0.39, the number that will be stored will not be 39/100 and will instead be 0.39000000000000001332267629550187848508358001708984375 which is 3512807709348987/9007199254740992 . You cannot get it to store 39/100 exactly in numeric form except by going symbolic

When you have numeric values stored in a table then what is output for disp() or giving the variable name depends on what your current format is set to. From your description you probably have it set to the default, format short e . If you were to command

format long g

and display the table you would see more decimal places, due to the difference between what the display formatting is and what is stored. If you command

format bank

then that just might work for you, provided that you do not mind if those 4e-07 show up as 0. format bank is two digits exactly after the decimal place.

For any custom display, you need to extract the values and format them yourself.

[Walter Roberson]

At least up to R2017a, floor() and ceil() only permit a second parameter when the first parameter is of type duration, in which case a time unit to round to may be given.

Answer 2

[JohnGalt]

If it's just a quick cleanup of the display of the numbers, you could just round the data in the table directly e.g.

array = rand(5,10);
tbl = array2table(array);
tbl.Variables =  round(tbl.Variables,1)

of course, this actually modifies the data so you might want to create a copy of your table first

Answer 3

[John BG]

Hi Maryam

this is John BG ( <mailto:[e-mail] [e-mail]> )

for each element of the table do the following

pull up 2 decimals, then apply the rounding ceiling flooring as preferred and bring down 2 least significant digits back to decimals

A=3.1416
floor(A*100)/100
= 3.14

or

ceil(A*100)/100
= 3.15

there's also the command round , it depends on how you want to approximate that you may want to chose one of these 3 commands.

.

if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?

To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>

Answer 4

[Roberto Osorio]

It's a pity that Matlab doesn't distinguish between significant and non-significant trailing zeros. If I round(2.99792) [this is the speed of light in units of 1e8 m/s] to 3 digits, I should get 3.00 (the two zeros are significant), not 3e8. The latter should be displayed only when you round to 1 digit.

[Walter Roberson]

No computer language that is based upon IEEE 754 Binary Floating Point keeps track of significant zeros, and no Intel x64 architecture works in decimal. The IBM Z9 series has an option for IEEE 754 Decimal Floating Point, but that does not keep track of significant zeros either.

[Roberto Osorio]

I don't mean the internal representation (which you change with the round function), but the display. Using sprintf or fprintf does the trick for a scalar or a row vector.

sprintf('%.2f %.2f',[2.99792 pi])
ans =
    '3.00 3.14'

Of course here the result is a char array. What I really would like is a generalization of 'format bank' for an arbitrary number of digits (other than 2) after the decimal dot.

>> format bank
>> [2.99792 pi]
ans =
          3.00          3.14
>> array2table([2.99792 pi])
ans =
  1×2 table
    Var1    Var2
    ____    ____
    3.00    3.14

[Walter Roberson]

Unfortunately matlab does not have the capability of user specified default format for disp and tables (and uitable)