readtable truncates rownames if using ReadRowNames

One of the options for "readtable" is "ReadRowNames".

Apparently, when "ReadRowNames" is true, Matlab silently truncates the length of rownames to a maximum of 63 characters.

However, if you manually assigned row names to a table in Matlab, they can be of arbitrary length. (e.g. myTable.Properties.RowNames = cellArrayOfVeryLongStrings works and does not truncate row names.)

No warning is given, and this "feature" is not mentioned in any documentation or Matlab tutorial on Tables.

Note that Matlab issues various warnings when, say, Variable Names for table are too long, non-unique, contain invalid characters, etc. The crime here is that Matlab automatically "formats" incoming rownames in "readtable" without any warning or notification.

Answer 1

[Peter Perkins]

cmo, you are correct, thank you for finding this bug. I will make a note to have it fixed. For the time being, you can read in the file with ReadRowNames set to false, and then assign the row names and delete the string variable.

Just out of curiosity, what names do you have that are more than 63 characters?

[Peter Perkins]

cmo, I really was asking about those long names. It helps to know how people are using MATLAB, and this seems like maybe a case we'd like to know about. Thanks.

[Julan Prasad]

Hi peter,

Still having this with Matlab readtable

[Julan Prasad]

doesn't seem it has been fixed, is someone able to help support?

[Steven Lord]

@Julan Prasad What release of MATLAB are you using? I suspect this is Bug Report 1295146 which is listed as affecting releases R2014a through R2015b and having been fixed in release R2016a. If you're using one of the affected releases, try upgrading to release R2016a or later.

[Ed Shen]

I'm using 2021b and I'm still seeing this issue.