simple question about how to change string to double value

hi~
I am a newbie in Labview~:P

And I come across with the question about how to change the string value"NSC-1234nA" to the double value 1234*10^-9. How can I do it?

如果是規則性的字串的話,我的建議是可以自己編碼,例如:u=10^-6,n=10^-9,可以自己先試看看