GUI Import data: Column names not recognized for large files

Version R2017b. When using the GUI: Home->Import data for csv files, I observe that the import data interface does not take over the column headers from the .csv file if the number of columns is large. I tested this with csv files containing 365 columns and 3285 columns. The large file contains copies of the data in the small files. For the first short file,the column names are recognized but not for the second file:

Is this intended or a known bug? I could not find a reference on MATLAB Answers.

Thank you!

[Jan]

Please post the CSV files also.

[Timo]

Added.

[Jan]

All headers in the first line are "bla", "bla", "bla", ... Isn't this nonsense? What about using different names?

[Timo]

This is a test file which allows recreating the problem. My original files contain private data.

Answer 1

[Prasanth Sunkara]

This behavior is intentional. In order for the import tool to meet performance expectations, it only processes a certain amount of a delimited file to try to find header and variable name information, among other details, and this limit is 1000 columns. Beyond this, the import tool will experience many delays in performance.

Please consider using Datastore for larger data-sets.

-Prasanth

[Timo]

Thank you for the very clear answer! Not knowing the reason for this behavior might confuse the user though (as it did for me). A pop-up note or similar to inform the user and point to alternatives would be helpful.