I want to write output files containing tabular datas (float values in lines and columns) from a C++ program.
I need to open those files later on with other languages/softwares (here python and paraview, but might change).
What would be the most efficient output format for tabular files (efficient for files memory sizes efficiency) that would be compatible with other languages ?
E.g., txt files, csv, xml, binarized or not ?
Thanks for advices
1- Your output files contain tabular data (float values in lines and columns), in other words, a kind of matrix.
2- You need to open those files later on with other languages/softwares
3- You want to have files memory sizes efficiency
That's said, you have to consider one of the two formats below:

CSV: if your data are very simple (a matrix of float without particualr structure)
JSON if you need a minimum structure for your files

These two formats are standard, supported by almost all the known languages and maintained softwares.
Last, if your data have a great complexity structure, prefer to look at a format like XML but the price to pay is then in the size of your files!
Hope this helps!
Which data files output format from C++ to be read in python (or other) is more size efficient?