65,000 x 306 xlsx import problem

I've used MATLAB for years but avoided dealing with large files until now. My spread sheet has azimuth, elevation and 76 frequencies with 4 columns each for a total of 306 columns. There are 65,000 rows of data. Except for row 1 it is all num.

When I use the import tool or a function produced by the import tool nothing happens. By nothing there is no variable in work space, the command >> never returns, there is no CPU, memory, or SSD activity. Otherwise MATLAB and Windows remain active, i.e. not locked up.

If I eliminate 3 of the 4 column associated with each freq reducing the data to 65k x 77 the Import tool will create a function and import a cell table. I then use cell2mat to process selected rows or columns. It does solve the noncontiguous columns problem but is a painful process.

Questions: 1 Is it possible to import non noncontiguous columns from a large XLSX file in a matrix (non cell) format? 2 There are a dozen import functions (e.g. importdata, importxls, readxls, etc). Which is most suitable to my problem?

Answer 1

[Sulaymon Eshkabilov]

Use readmatrix() or readtable() which are efficient and fast.