# [R] [EXTERNAL] RE: I need to create new variables based on two numeric variables and one dichotomize conditional category variables.

Jorgen Harmse JH@rm@e @end|ng |rom roku@com
Fri Nov 3 23:26:38 CET 2023

```Yes, that will halve the number of multiplications.

If you�re looking for such optimisations then you can also consider ifelse(G=='male', 65L, 58L). That will definitely use less time & memory if WC is integer, but the trade-offs are more complicated if WC is floating point.

Regards,
Jorgen Harmse.

From: avi.e.gross using gmail.com <avi.e.gross using gmail.com>
Date: Friday, November 3, 2023 at 16:12
To: Jorgen Harmse <JHarmse using roku.com>, r-help using r-project.org <r-help using r-project.org>, mkzaman.m using gmail.com <mkzaman.m using gmail.com>
Subject: [EXTERNAL] RE: [R] I need to create new variables based on two numeric variables and one dichotomize conditional category variables.
Just a minor point in the suggested solution:

df\$LAP <- with(df, ifelse(G=='male', (WC-65)*TG, (WC-58)*TG))

since WC and TG are not conditional, would this be a slight improvement?

df\$LAP <- with(df, TG*(WC - ifelse(G=='male', 65, 58)))

-----Original Message-----
From: R-help <r-help-bounces using r-project.org> On Behalf Of Jorgen Harmse via
R-help
Sent: Friday, November 3, 2023 11:56 AM
To: r-help using r-project.org; mkzaman.m using gmail.com
Subject: Re: [R] I need to create new variables based on two numeric
variables and one dichotomize conditional category variables.

df\$LAP <- with(df, ifelse(G=='male', (WC-65)*TG, (WC-58)*TG))

That will do both calculations and merge the two vectors appropriately. It
will use extra memory, but it should be much faster than a 'for' loop.

Regards,
Jorgen Harmse.

------------------------------

Message: 8
Date: Fri, 3 Nov 2023 11:10:49 +1030
From: "Md. Kamruzzaman" <mkzaman.m using gmail.com>
To: r-help using r-project.org
Subject: [R] I need to create new variables based on two numeric
variables and one dichotomize conditional category variables.
Message-ID:
<CAGbxoeGjsxZKQ6qijEMq-X-5doqnQQS1jjPDDrGT6hH5xWqOKQ using mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

Hello Everyone,
I have three variables: Waist circumference (WC), serum triglyceride (TG)
level and gender. Waist circumference and serum triglyceride is numeric and
gender (male and female) is categorical. From these three variables, I want
to calculate the "Lipid Accumulation Product (LAP) Index". The equation to
calculate LAP is different for male and females. I am giving both equations
below.

LAP for male = (WC-65)*TG
LAP for female = (WC-58)*TG

My question is 'how can I calculate the LAP and create a single new column?

Your cooperation will be highly appreciated.

With Regards

*--------------------------------*

*Md Kamruzzaman*

*PhD **Research Fellow (**Medicine**)*
Discipline of Medicine and Centre of Research Excellence in Translating
Nutritional Science to Good Health
Adelaide Medical School | Faculty of Health and Medical Sciences
The University of Adelaide

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