Finding location of double in string

[Uber Meister]

I know how to find the occurrences of a character in a string, but I have a more specific problem.

For example, consider the string:
" C 1.3825 4.0000 12.0000 1.9133 0.1853 0.9000 -1.1359 4.0000 "

I want to extract a vector that contains the positions of every first character for each number.

For the example above, the output should be a vector with elements [6 15 23 33 etc...]. These are the positions of the first character for every number.

I need to be able to do this for any arbitrary string with any arbitrary amount of numbers and characters in it (I also need to account for negative numbers).

Any tips?

[Yay295]

Iterate through the string for a space char. If you find one, check if the next char is a number. If it is, save the location of that number to your vector.