memmapfile & char inputs

Hi all, as I have to work with a massive ammunt of data, I have decided to give a try to memmapfile. As moust of you already know this allow me to map matlab to the the file without the need to import into matlab workspace.

The issue thought is the following: the txt file i am mapping contains both strings (i know which columns contain strings) and NA. I know I can specify multiple data format but it seems there's not the possibility to specify a char class.

Can I have some hint or a workaround to solve my problem?

Thanks!

Graziano

[Jan]

What is "NA"?

[Oleg Komarov]

Should be NaN/missing

Answer 1

[Jan]

MEMMAPFILE cannot handle files which contain blocks of different size, e.g. text lines with varying length. So either use MEMMAPFILE to treat the complete file as a single stream of bytes, or decide to use the standard methods for serialized file reading.

Look in the examples of "doc memmapfile".

[Graziano]

Thank you very much for your answer. I do appreciate it a lot. By serialized reading do you mean functions like fread? ...

[Jan]

Yes. FREAD, FGETL, FGETS might by appropriate.