Using regular expression to extract numeric data from text file

Hi, I have a text file containing a bunch of lines with the following format:

"Triangle(Vector3D(-0.125, -0.375, 0), Vector3D(0.125, -0.375, 0.166396), Vector3D(0.125, -0.375, 0))"

I would like to extract the numeric values contained within the parentheses.

Right now I am attempting to make a matrix Mx9, where M is the number of lines in the text file, and the 9 comes from the 3 elements of the three vectors. I try doing this using a regular expression and capture groups:

string = fileread('triangle_positions.txt')
expression = '(-?\d+\.?\d*),\s(-?\d+\.?\d*),\s(-?\d+\.?\d*)'
tokens = regexp(string, expression, 'tokens');

The result is a "cell" containing the values as strings. For a single line I get a "1x3 cell" where each cell contains the coordinates of the vector as strings.

How would you convert this into a regular matlab matrix?

Thanks in advance

Søren

Answer 1

[Stephen23]

mat = str2double(vertcat(tokens{:}))

You will need to reshape the matrix, e.g.:

mat = reshape(mat.',9,[]).'

See:

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists

https://www.mathworks.com/help/matlab/ref/str2double.html

[Søren Holm-Petersen]

Thanks!