Can I add units to the table?

Can I add units to the variables in the table? I have searched for information and I could not find anything, it can only be done in numbers ...please help

[Matthew Anderson]

Agree, super annoying that when you put units into a table - they aren't displayed.

[Lorenzo Chiaverini]

Idem, it would be great if they were displayed as you showed

[Greg]

This would be a great feature to add. Units are very important and would help my work a ton.

[dpb]

@Greg -- agreed, and re: @Walter Roberson's comment that the table is not intended for display but that it would seem a minor thing to add, the present format already has a blank line there; it wouldn't take up any more room on the screen if MW would just stuff the units in there if they exist. (Speaking of blank lines, I've always wished they would do away with the one after the line before the first data row...)

t=array2table([[0:2].',rand(3,1)],'VariableNames',{'Time','Velocity'});
t.Properties.VariableUnits={'sec','mph'}

t = 3x2 table
    Time    Velocity
    ____    ________

     0      0.18719 
     1      0.67738 
     2      0.28007 

[Paul]

Does the VariableUnits property have any built-in functional use?

Or is it just there to alllow the user to keep track of the units and provide an ability to do a unit checking in user-defined functions?

[Walter Roberson]

@Paul

The units are shown with summary () -- but that is about the limit

[Paul]

Sure, enough. They don't even get checked when co[n]catenating tables.

T1 = table([1;2;3],'VariableNames',{'x'}); T1.Properties.VariableUnits = {'sec'};
T2 = table(2*[1;2;3],'VariableNames',{'x'}); T2.Properties.VariableUnits = {'m'};
summary([T1;T2])

Variables:

    x: 6x1 double

        Properties:
            Units:  sec
        Values:

            Min           1   
            Median      2.5   
            Max           6   

summary([T2;T1])

Variables:

    x: 6x1 double

        Properties:
            Units:  m
        Values:

            Min           1   
            Median      2.5   
            Max           6   

Answer 1

[Raj]

"Can I add units to the variables in the table?" Yes you can. You can specify units for each variable in the table by modifying the table property,

% |VariableUnits|. 

Specify the variable units as a cell array of character vectors.

Something like this:

table (W,T,Pe,P)
T.Properties.VariableUnits = {'Rad/S','NM','N','N'}; % what I could make out from your picture. Please correct if wrong.

Or Do you want the units to get displayed on your table? Please be clear.

[Diego Guarachi]

END=[Qt Ht Hbt Wt Tt Pet Pt Nt NPSHdt];

names={'QCau','Hpump','Hsystem','W','T','Pe','P','N','NPSHd'};
T = array2table(END,'VariableNames',names);
T.Properties.VariableUnits = {'m3/s','m','m','rad/s','N*m','W','W','%','m'};
disp(T)

Should I implement it like that? It did not work..

[Raj]

That's what i asked. The units have got defined. They don't get displayed by default here. If you open the table in workspace, the first row will have a drop down option where you will be able to see the units for each variable as you have defined. Or try using

summary(T)

You'll be able to see the defined units.

[Shan Alan David]

I have a similar question to this. I am trying to print the units next to the values in the table.

[Walter Roberson]

table() objects are not designed for display purposes. There is no facility to format the entries in custom ways, and there is no facility to display units along side the entries.

[Andreas Lobinger]

Is there a facility to deal with multiline VariableNames? Then one could do Units in the second line manually. Or, what actually is the infrastructure to display tables?

[Walter Roberson]

>> t = table((1:5).', 'VariableNames', {sprintf('Depth\n[mm]')})

t =

5×1 table

Depth↵[mm]

__________

1

2

3

4

5

That ↵ character is literally what is output: the code specifically searches for newline characters and replaces them with that, and it specifically replaces carriage return characters with ←

The "actually" infrastructure to display tables is the code in toolbox/matlab/datatypes/tabular/@tabular/disp.m . In R2020b look at line 75:

    % Replace LF with "knuckle" tab with "arrow", and CR with "backarrow".
    % This also truncates long lines, but is irrelevant here.
    % Replaces hyperlinks with no display text with ''.
    for iv = 1:numel(varNames)
        varNames(iv) = matlab.internal.display.truncateLine(varNames(iv),10000);
    end

The truncateLine call is the one that does the replacement.

Is there a facility to deal with multiline VariableNames: Yes, the facility explicitly converts them to not be multi-line.

[Andreas Lobinger]

I see - and thanks for the long explaination. Can you provide a "why" here? I'd assume a lot of researchers want to put units in tables - and adding to the variable name eats up screen space, so a second line looks like the natural solution.

[Walter Roberson]

table() are not designed for presentation purposes. Report Generator has facilities for better output of tables.

That said, it would seem to me to be a small thing to add the units or the Variable Description information (which might be the original names of the variables.) It could even be made into properties as to whether to display them or not. I don't know why Mathworks has not done this.

table() could also benefit from a per-variable format specification... among other things.

[dpb]

t=array2table([[0:2].',rand(3,1)],'VariableNames',{'Time','Velocity'});
t.Properties.VariableUnits={'sec','mph'}

t = 3x2 table
    Time    Velocity
    ____    ________

     0      0.011763
     1       0.85573
     2       0.24784

Indeed to all...there's already room for them with a blank line just waiting to be used for something besides wasted white space.

Answer 2

[KSSV]

It is not allowed...may be you can use something like this:

varNames = {'Name', 'Age_in_Years'} ; 
varTypes = {'string','double'};
s = {'Tom' ; 'Dick' ; 'Hary'} ; 
a = [20 ;21; 24] ;
T = table(s,a) ;
T.Properties.VariableNames = varNames