How to round numbers in tables?

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Hao Tang
Hao Tang 2018-2-22
评论： the cyclist 2021-10-2
How can I round a number in a matlab table after it does its calculation? I have a cell that calculates the value to be 0.009999998 but I want it to read 0.01. I tried using format short g in the script but that didn't work.

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回答（3 个）

the cyclist
the cyclist 2018-2-22
编辑：the cyclist 2018-2-22
Use the round function.
You could have discovered this for yourself by typing
docsearch round
in the MATLAB command window, or typing
round matlab
into Google.
Note that there is a difference between the value that is calculated/stored, and how it is displayed. The format command is about the display.
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Bill Tubbs
Bill Tubbs 2021-10-2
I found the round function doesn't work with tables:
>> round(table(randn(3,4)), 3)
Error using round
First argument must be a numeric, logical, or char array.
So this answer was not helpful.
the cyclist
the cyclist 2021-10-2
See my comment on your "answer" below.

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Star Strider
Star Strider 2018-2-22
If you do not have the R2015a (I believe that is the correct release) that introduced the new round function, this anonymous function emulates it:
roundn = @(x,n) round(x .* 10.^n)./10.^n; % Round ‘x’ To ‘n’ Digits, Emulates Latest ‘round’ Function
x = 0.009999998;
xr = roundn(x,2)
xr =
0.01
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Lance Yarbrough
Lance Yarbrough 2019-4-14
编辑：Lance Yarbrough 2019-4-14
THANK YOU!! Looking for this answer forr most of the DAY.

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Bill Tubbs
Bill Tubbs 2021-10-2
Is here a way to use the round function with tables?
Simply using round(my_table, 3) does not work:
t = array2table(randn(3, 4), 'VariableNames', {'A', 'B', 'C', 'D'}, ...
'RowNames', {'1', '2', '3'});
round(t, 3)
Output:
Error using round
First argument must be a numeric, logical, or char array.
I found this solution but it's quite convoluted:
t2 = t; t2{:, :} = round(t.Variables, 3)
Output:
t2 =
3×4 table
A B C D
______ ______ ______ ______
1 0.722 0.187 -0.439 -0.888
2 2.585 -0.082 -1.795 0.1
3 -0.667 -1.933 0.84 -0.545
Surely there is a better way...
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Bill Tubbs
Bill Tubbs 2021-10-2
Thanks but this doesn't preserve the row and column names, and possibly other attributes of the table.
I found the same question answered here by Steven Lord STAFF MVP.
the cyclist
the cyclist 2021-10-2
OK. I can't tell from this comment whether you ended up with a solution that works for you.
If not, you might want to start a new question with your specific needs, rather than commenting and "answering" on an older question. You'll typically get more eyes on it if you do.

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