remove extra values from a double variable

[Reema lutfi]

I want to multiply 2 variables (Strength_unit x ratio and generate a new variable that take the new value, but the proble is strength unit have extra numbers and details that I am not intrested I just need the first value before the node. for example for first row I just need 5. how can I do this

Strength unit	ratio
5.000microgram/1.000hour	1.8
15.000mg	015

[Hemanshu Kumar]

clear
input str30 strength_unit float    ratio
"5.000microgram/1.000hour"    1.8
"15.000mg"                    015
end

gen strength_num = real(ustrregexs(0)) if ustrregexm(strength_unit,"^([0-9.]+)")

which produces:

. li , noobs

  +---------------------------------------------+
  |            strength_unit   ratio   streng~m |
  |---------------------------------------------|
  | 5.000microgram/1.000hour     1.8          5 |
  |                 15.000mg      15         15 |
  +---------------------------------------------+

[Reema lutfi]

Thank you, the code worked