Calculate value from an equation using Field Calculator Python/VB Script

Question

I wanted to calculate a result value from 3 fields using an equation.

VBScript or Python codes are also accepted..:-)

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the equation is RESULT= [(R^2/3)(S^1/2)]/n..

is that R to the power of 2 divided by 3?? Not sure what the ^ operator is here. — Michael Miles-Stimson, Nov 11 '14 at 4:20
Would you be able to edit your question to show what you have already tried in the Field Calculator, please? — PolyGeo♦, Nov 11 '14 at 4:44
@PolyGeo: i have not tried anything yet because it looks like python/vb script and I am a newbee in coding. I have search many sites and I think coding is really needed here to solve my problem. hope you can help me. — almer_cris, Nov 11 '14 at 5:48

PolyGeo · Answer 1 · 2014-11-11 06:10:26Z

Your expression looks incomplete but I am assuming that the first part of it is trying to find the square of the cube root.

My test below on that when R had a value of 8 returned the expected value of 4 to the RESULT field

RESULT =

[R] ^ ( 2 / 3 )

The above worked when the parser is set to VBScript.

With Python, there is hopefully an easier way but I got it to work with:

RESULT =

math.pow(!R!,( float(2) / float(3) ))

My testing used ArcGIS 10.2.2 for Desktop on a file geodatabase feature class.

Perhaps your whole expression in VBScript is:

([R]^(2/3))*([S]^(1/2))/[n]

thanks a lot..u really help me solve my problem..till next time..:-) — almer_cris, Nov 12 '14 at 1:22

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