How to make a grouped boxplot of measurements data from five days?

Hi,

I have a 46x5 matrix with measurement data from 46 points taken on five days, called MyData.

The 46 measurement points belong to three groups. They are saved in a 46x1 vector called Site, with values 1, 2 or 3 representing the three groups.

I'm trying to create a grouped boxplot using:

MyData = rand(46,5);
Site = randi([1 3],46,1);
boxplot(MyData,Site);

but I'm getting an error:

Error using boxplot>straightenX (line 970)
G must be the same length as X or the same length as the number of columns in X.

Error in boxplot (line 274)
[xDat,gDat,origRow,xlen,gexplicit,origInd,origNumXCols] = straightenX(x,g);

G and X actually do have the same length (46), but I assume Matlab doesn't like the fact that the number of columns in X is larger than one.

Does any of you know how to solve it? My goal is to make a boxplot similar to this (just made in Powerpoint:)

Answer 1

[Corymbiamaculata]

I found the answer myself; updating in case someone has a similar problem.

MyData = rand(46,5);
Site = randi([1 3],46,1);
MyDataNew = reshape(MyData,size(MyData,1)*size(MyData,2),1); % reshape into one column

MeasureDay = repelem(1:5,[size(MyData,1)],[1]); % new variable with values representing measurement days
MeasureDay = reshape(MeasureDay,size(MeasureDay,1)*size(MeasureDay,2),1); % reshape into one column
Site = repmat(Site,5,1); % reshape into one column
boxplot(MyDataNew,[Site,MeasureDay]); % two grouping variables used together