Round all values in table

2021 10 25
2 个回答
更新时间：2025 7 15
27 次查看（30 天）

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Hi,
I have a table with calculated values. Now I want to round all values to 2 decimals. How can I do that in once for the whole table?

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回答（2 个）

Scott MacKenzie
Scott MacKenzie 2021-10-25
编辑：Scott MacKenzie 2021-10-25
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1 个投票

Ran in:
I think this achieves what you are after:
% test data
T1 = array2table(rand(5))
T1 = 5×5 table
Var1 Var2 Var3 Var4 Var5 _________ _______ _______ ________ ________ 0.0024079 0.97172 0.41667 0.027209 0.079337 0.14919 0.17995 0.58257 0.46413 0.99968 0.56165 0.79083 0.06821 0.18682 0.23824 0.31412 0.6835 0.82666 0.49151 0.12438 0.78186 0.66873 0.07059 0.86243 0.32011
% rounded to 2 decimal places
T2 = array2table(round(T1{:,:},2))
T2 = 5×5 table
Var1 Var2 Var3 Var4 Var5 ____ ____ ____ ____ ____ 0 0.97 0.42 0.03 0.08 0.15 0.18 0.58 0.46 1 0.56 0.79 0.07 0.19 0.24 0.31 0.68 0.83 0.49 0.12 0.78 0.67 0.07 0.86 0.32
Andrew Sandeman
Andrew Sandeman 2025-7-14
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0 个投票

Ran in:
Another solution using varfun()
% test data
T = array2table(rand(5))
T = 5×5 table
Var1 Var2 Var3 Var4 Var5 __________ _________ _________ ________ ________ 0.10584 0.27303 0.0067048 0.58837 0.063311 0.45211 0.12874 0.22154 0.4381 0.57343 0.59635 0.64793 0.89923 0.64467 0.48561 0.75997 0.0090159 0.33324 0.42146 0.60051 0.00011342 0.11944 0.35647 0.059849 0.066758
% round data in table to 2 d.p.
varfun(@(x)round(x,2), T)
ans = 5×5 table
Fun_Var1 Fun_Var2 Fun_Var3 Fun_Var4 Fun_Var5 ________ ________ ________ ________ ________ 0.11 0.27 0.01 0.59 0.06 0.45 0.13 0.22 0.44 0.57 0.6 0.65 0.9 0.64 0.49 0.76 0.01 0.33 0.42 0.6 0 0.12 0.36 0.06 0.07
The only difference is the variable names.

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Walter Roberson
Walter Roberson 2025-7-14
If you use the varfun() option InputVariables=@numeric then you can have the rounding apply only to the numeric portions of the table.
However, variables not selected by the @isnumeric will simply not appear in the output table, and the variables that do appear will have 'round_' as a prefix. This is not exactly the most convenient for post-processing.
Another approach is to create a helper function along the lines of
function out = conditional_round2(in)
if isnumeric(in)
out = round(in,2);
else
out = in;
end
end
and then
new_T = varfun(@conditional_round2, T);
new_T.Properties.VariableNames = regexprep(T.Properties.VariableNames, '^[^_]*_', '', 'once');
Andrew Sandeman
Andrew Sandeman 2025-7-14
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Ran in:
Thanks very much, I had no idea about the InputVariables option to varfun(), something I definitely could have used in the past!
What about this, still using varfun():
% test data
t = table(rand(5,1), repelem("a",5,1))
t = 5×2 table
Var1 Var2 ________ ____ 0.4024 "a" 0.21798 "a" 0.070511 "a" 0.1205 "a" 0.72754 "a"
% round data in table to 2 d.p.
t(:,"Var1") = varfun(@(x)round(x,2), t, InputVariables=@isnumeric)
t = 5×2 table
Var1 Var2 ____ ____ 0.4 "a" 0.22 "a" 0.07 "a" 0.12 "a" 0.73 "a"
The other method, whilst also good, for me coming up with that regex pattern is still a mental speedbump. However, I can see an extension to conditionalRound. I would call it a conditionalFunction, and should you want to say round to 2 d.p. if is column is numeric, do something else if isstring e.g.
function out = conditionalFunction(in)
if isnumeric(in)
out = round(in,2);
elseif isstring(in)
% do something to strings
else
out = in;
end
end
Walter Roberson
Walter Roberson 2025-7-14
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Ran in:
That's an interesting use of table assignment.
Needs more work if there could be multiple output variables.
t = table(rand(5,1), rand(5,1), repelem("a",5,1))
t = 5×3 table
Var1 Var2 Var3 _______ _______ ____ 0.89086 0.66185 "a" 0.83846 0.33959 "a" 0.78412 0.42468 "a" 0.34779 0.68343 "a" 0.49041 0.28647 "a"
outvars = t.Properties.VariableNames(varfun(@isnumeric,t,OutputFormat="uniform"))
outvars = 1×2 cell array
{'Var1'} {'Var2'}
t(:,outvars) = varfun(@(x)round(x,2), t, InputVariables=outvars)
t = 5×3 table
Var1 Var2 Var3 ____ ____ ____ 0.89 0.66 "a" 0.84 0.34 "a" 0.78 0.42 "a" 0.35 0.68 "a" 0.49 0.29 "a"
Andrew Sandeman
Andrew Sandeman 2025-7-15
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Ran in:
And here it is wrapped up in a function.
Awesome! I feel like with some documentation it might be worth putting on the file exchange?
t = table(rand(5,1), rand(5,1), repelem("a",5,1))
t = 5×3 table
Var1 Var2 Var3 _______ ________ ____ 0.45139 0.33976 "a" 0.6767 0.59527 "a" 0.46407 0.070445 "a" 0.87703 0.88928 "a" 0.30553 0.68711 "a"
conditionalVarfun(t, @isnumeric, @(x)round(x,2))
ans = 5×3 table
Var1 Var2 Var3 ____ ____ ____ 0.45 0.34 "a" 0.68 0.6 "a" 0.46 0.07 "a" 0.88 0.89 "a" 0.31 0.69 "a"
%% functions
function t = conditionalVarfun(t, fh_condition, fh_operation)
% t (table)
% fh_condition e.g. @isnumeric
% fh_operation e.g. @(x)round(x,2)
p = inputParser;
p.addRequired("t", @istable)
p.addRequired("fh_condition", @isfunctionhandle)
p.addRequired("fh_operation", @isfunctionhandle)
p.parse(t, fh_condition, fh_operation)
t = p.Results.("t");
fh_condition = p.Results.("fh_condition");
fh_operation = p.Results.("fh_operation");
outvars = t.Properties.VariableNames(varfun(fh_condition,t,OutputFormat="uniform"));
t(:,outvars) = varfun(fh_operation, t, InputVariables=outvars);
end
function bool = isfunctionhandle(x)
bool = isa(x, 'function_handle');
end

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