Error using matlab.int​ernal.math​.checkData​Variables Invalid grouping variables.

kindly help me solve this issue

load("stormData"); 
 summaryRegionCosts = groupsummary(stormData, "stormData.Region",['min','max','median','mean'] , "stormData.Total_Cost")
   stormDataPos = stormData.Total_cost> 0 
  summaryRegionPosCosts =   groupsummary(stormData,  "stormData.Region",   ['min','max','median','mean'],"stormData.stormDataPos")
  
  

[Juan Carlos Hernandez]

Hi,

Here is your problem solved:

load("stormData"); 
summaryRegionCosts=groupsummary(stormData,"Region",["min","median","mean","max"],"Total_Cost")
stormDataPos=stormData(stormData.Total_Cost>=1,:)
summaryRegionPosCosts=groupsummary(stormDataPos,"Region",{"min","median","mean","max"},"Total_Cost")

Answer 1

[Steven Lord]

The second input for the groupsummary function as you're calling it should be the name of a variable in your table. "stormData.Region" isn't the name of a variable, it's an expression that would extract a variable in the table. Try using just "Region" in your call instead.

[Umair Ejaz]

ok let me try

[Umair Ejaz]

[Umair Ejaz]

it is showing this error now

[Walter Roberson]

"To specify multiple computations at a time, list the options in a cell array, such as {'mean','median'} or {myFun1,myFun2}."

You did not use a cell array.

[Umair Ejaz]

[Umair Ejaz]

still these errors

[Simon Chan]

Could you show us what is the output of the following code?

stormData.Properties.VariableNames

[Umair Ejaz]

ok

[Umair Ejaz]

[Walter Roberson]

Do not use a cell array of string objects. Use either a cell array of character vectors or else a string vector.

That is, {'this', 'that'} or ["this", "that"] but not {"this", "that"}

[Steven Lord]

Your table doesn't have a variable named Region. For that second input in your call to groupsummary you need to use one of those 13 names in the output above. SuperRegion seems closest to Region.

[Walter Roberson]

"Region" is present if you look back to the table output in the original Question.

It does not appear in the list here because the list here truncated, with only 8 variable names visible on the list before the right hand margin, but the column count shows the second line picks up at 12. So 3 variables are missing, and the original table shows that Region is right before SuperRegion.

[Umair Ejaz]

Region is present but it is written on other side

[Umair Ejaz]

https://www.mathworks.com/matlabcentral/answers/1782575-error-using-matlab-internal-math-checkdatavariables-invalid-grouping-variables#comment_2326095

i have tried it but still not working

[Walter Roberson]

You are attempting to pass in a logical mask stormDatapos as the 4th parameter to groupsummary, with the first parameter being a table

When you use 4 parameters to groupsummary and the first one is a table, the permitted syntaxes are

G = groupsummary(T,GROUPVARS,GROUPBINS,METHOD)
G = groupsummary(T,GROUPVARS,METHOD,DATAVARS)

Your {'min', 'max', 'median', 'mean'} or ["min", "max", "median", "mean"] is not grouping bins, so the first of the two possibilities does not apply.

Your logical vector is not a data variable name within the table, so the second of the two possibilities does not appy.

If you want to summarize only for a subset of a table, you need to construct the subset first and summarize on it. For example,

sdss = stormData(stormDataPos, :);
summaryRegionPostCosts = groupsummary(sdss, "Region", ["min", "max", "median", "mean"])

In practice you will probably need to add a list of variables to apply the summary to, as it is not clear that taking mean() of your categorical SuperRegion is meaningful.