I wish to read values from a text file using  GETTEXTFILE . The file would have a few header lines such as: 

Interferogram between reference beam and Configuration 4
0.6328 µm at 0.0000 (deg).
Peak to Valley = 9.1730 waves, Fringes/Wave = 2.0000.
Surface: Image (image)
Exit Pupil Diameter: 1.0002E+002 Millimeters
Xtilt = 0.00, Ytilt = 0.00.

I am interested in grabbing the Peak to Valley value of  9.1730 and returning it as a numerical value to the merit function using the ZPLM Merit Function Editor Operand. 

While there is a way to convert numerical values to strings using the $STR() string function, would there be an equivalent command to do the reverse?