String to number conversion.
X = STR2NUM(S) converts the string S, which should be an
ASCII character representation of a numeric value, to MATLAB's
numeric representation. The string may contain digits, a decimal
point, a leading + or - sign, an 'e' preceeding a power of 10 scale
factor, and an 'i' for a complex unit.
If the string S does not represent a valid number, STR2NUM(S)
returns the empty matrix.
See also NUM2STR , HEX2NUM .