[R] Set a zero at minimum row by group

[arun]

Hi,
You could also use:
df$x_new<-unlist(lapply(split(df,df$ID),function(x) as.numeric(min(x[,2])!=x[,2])))
df
#  ID T x x_new
#1  1 1 1     0
#2  1 2 1     1
#3  1 3 1     1
#4  2 1 1     0
#5  2 4 1     1
#6  3 3 1     0
#7  3 5 1     1
#8  3 6 1     1
#9  3 8 1     1
A.K.

----- Original Message -----

From: Jose Iparraguirre <Jose.Iparraguirre at ageuk.org.uk>
To: Carlos Nasher <carlos.nasher at googlemail.com>; "r-help at r-project.org" <r-help at r-project.org>
Cc: 
Sent: Tuesday, December 18, 2012 11:32 AM
Subject: Re: [R] Set a zero at minimum row by group

There may be more efficient ways, but here's one:

> x_new <- rep(0,nrow(df))
> x_new <- ifelse(df$T==min(T),0,1)

Regards,

José

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf Of Carlos Nasher
Sent: 18 December 2012 14:10
To: r-help at r-project.org
Subject: [R] Set a zero at minimum row by group

Dear R Helpers,

I'm struggling with a data preparation problem. I feel that it is a quite
easy task but I don't get it done. I hope you can help me with that.

I have a data frame looking like this:

ID <- c(1,1,1,2,2,3,3,3,3)
T <- c(1,2,3,1,4,3,5,6,8)
x <- rep(1,9)
df <- data.frame(ID,T,x)

>df
ID T x
1 1 1
1 2 1
1 3 1
2 1 1
2 4 1
3 3 1
3 5 1
3 6 1
3 8 1

I want to manipulate the x column in a way that for each customer (ID) at
the minimum of T the x value is set to zero. The result should look like
this:

ID T x x_new
1 1 1     0
1 2 1     1
1 3 1     1
2 1 1     0
2 4 1     1
3 3 1     0
3 5 1     1
3 6 1     1
3 8 1     1

I already tried the aggregate() and apply() function, but I don't get the
result I'm looking for. I would glad if you could help me out.

Best regards,
Carlos

    [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Wrap Up and Run 10k is back! 

Also, new for 2013 – 2km intergenerational walks at selected venues. So recruit a buddy, dust off the trainers and beat the winter blues by 
signing up now:

http://www.ageuk.org.uk/10k

                 Milton Keynes | Oxford | Sheffield | Crystal Palace | Exeter | Harewood House, Leeds | 
                                 Tatton Park, Cheshire | Southampton | Coventry



Age UK Improving later life

http://www.ageuk.org.uk




-------------------------------
Age UK is a registered charity and company limited by guarantee, (registered charity number 1128267, registered company number 6825798). 
Registered office: Tavis House, 1-6 Tavistock Square, London WC1H 9NA.

For the purposes of promoting Age UK Insurance, Age UK is an Appointed Representative of Age UK Enterprises Limited, Age UK is an Introducer 
Appointed Representative of JLT Benefit Solutions Limited and Simplyhealth Access for the purposes of introducing potential annuity and health 
cash plans customers respectively.  Age UK Enterprises Limited, JLT Benefit Solutions Limited and Simplyhealth Access are all authorised and 
regulated by the Financial Services Authority. 
------------------------------

This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are 
addressed. If you receive a message in error, please advise the sender and delete immediately.

Except where this email is sent in the usual course of our business, any opinions expressed in this email are those of the author and do not 
necessarily reflect the opinions of Age UK or its subsidiaries and associated companies. Age UK monitors all e-mail transmissions passing 
through its network and may block or modify mails which are deemed to be unsuitable.

Age Concern England (charity number 261794) and Help the Aged (charity number 272786) and their trading and other associated companies merged 
on 1st April 2009.  Together they have formed the Age UK Group, dedicated to improving the lives of people in later life.  The three national 
Age Concerns in Scotland, Northern Ireland and Wales have also merged with Help the Aged in these nations to form three registered charities: 
Age Scotland, Age NI, Age Cymru.










______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.