Re: [R] Calculating number of elapsed days from starting date
Hi,
You can also use either of these:
data$date <- as.Date(data$date,format="%m/%d/%y")
data$Days<-as.vector(sapply(lapply(split(data,data$Person),`[`,2),function(x)
difftime(x[,1],x[1,],units="days")))
#or
data$Days<-as.vector(sapply(lapply(split(data,data$Person),`[`,2),function(x)
x[,1]-x[1,]))
#or
data$Days<-unlist(lapply(lapply(split(data,data$Person),`[`,2),function(x)
difftime(x[,1],x[1,],units="days")))
data
data
# Person date Days
#1 bob 2000-01-01 0
#2 bob 2000-01-02 1
#3 bob 2000-01-03 2
#4 dave 2000-01-07 0
#5 dave 2000-01-08 1
#6 dave 2000-01-10 3
#7 kevin 2000-01-02 0
#8 kevin 2000-01-03 1
#9 kevin 2000-01-04 2
A.K.
- Original Message -
From: Marcel Curlin
To: r-help@r-project.org
Cc:
Sent: Thursday, September 27, 2012 1:16 AM
Subject: [R] Calculating number of elapsed days from starting date
Hi
I have data for events in rows, with columns for person and date. Each
person may have more than one event;
tC <- textConnection("
Person date
bob 1/1/00
bob 1/2/00
bob 1/3/00
dave 1/7/00
dave 1/8/00
dave 1/10/00
kevin 1/2/00
kevin 1/3/00
kevin 1/4/00
")
data <- read.table(header=TRUE, tC)
close.connection(tC)
rm(tC)
I would like to add a new column to my dataframe containing the calculated
number of elapsed days from the starting date for each person. So the new
dataframe would read
Person date Days
bob 1/1/00 0
bob 1/2/00 1
bob 1/3/00 2
dave 1/7/00 0
dave 1/8/00 1
dave 1/10/00 3
kevin 1/2/00 0
kevin 1/3/00 1
kevin 1/4/00 2
Not sure how to do this, tried looking through the forum but didn't find
anything that seemed to apply. Suggestions appreciated.
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Re: [R] Calculating number of elapsed days from starting date
On 27-09-2012, at 07:16, Marcel Curlin wrote:
> Hi
> I have data for events in rows, with columns for person and date. Each
> person may have more than one event;
>
> tC <- textConnection("
> Persondate
> bob 1/1/00
> bob 1/2/00
> bob 1/3/00
> dave 1/7/00
> dave 1/8/00
> dave 1/10/00
> kevin 1/2/00
> kevin 1/3/00
> kevin 1/4/00
> ")
> data <- read.table(header=TRUE, tC)
> close.connection(tC)
> rm(tC)
>
> I would like to add a new column to my dataframe containing the calculated
> number of elapsed days from the starting date for each person. So the new
> dataframe would read
>
> PersondateDays
> bob 1/1/00 0
> bob 1/2/00 1
> bob 1/3/00 2
> dave 1/7/00 0
> dave 1/8/00 1
> dave 1/10/00 3
> kevin 1/2/00 0
> kevin 1/3/00 1
> kevin 1/4/00 2
>
> Not sure how to do this, tried looking through the forum but didn't find
> anything that seemed to apply. Suggestions appreciated.
You could do this
DF$realdate <- as.Date(as.character(DF$date),format="%m/%d/%y")
DF$Days <- ave(as.numeric(DF$realdate), by=DF$Person, FUN=function(x) x-x[1])
If you don't want the as.character then you should add stringsAsFactors=FALSE
to the read.table argument list.
Berend
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Re: [R] Calculating number of elapsed days from starting date
On 27/09/12 17:16, Marcel Curlin wrote:
Hi
I have data for events in rows, with columns for person and date. Each
person may have more than one event;
tC <- textConnection("
Person date
bob 1/1/00
bob 1/2/00
bob 1/3/00
dave1/7/00
dave1/8/00
dave1/10/00
kevin 1/2/00
kevin 1/3/00
kevin 1/4/00
")
data <- read.table(header=TRUE, tC)
close.connection(tC)
rm(tC)
I would like to add a new column to my dataframe containing the calculated
number of elapsed days from the starting date for each person. So the new
dataframe would read
Person dateDays
bob 1/1/00 0
bob 1/2/00 1
bob 1/3/00 2
dave1/7/00 0
dave1/8/00 1
dave1/10/00 3
kevin 1/2/00 0
kevin 1/3/00 1
kevin 1/4/00 2
Not sure how to do this, tried looking through the forum but didn't find
anything that seemed to apply. Suggestions appreciated.
X <- data
X$date <- with(X,as.Date(date,format="%m/%d/%y"))
X$Days <- unlist(with(X,tapply(date,Person,function(x){x-x[1]})))
And then if you *really* want to keep that shaganappi date format:
X$date <- data$date
X
# Giving:
Persondate Days
1bob 1/1/000
2bob 1/2/001
3bob 1/3/002
4 dave 1/7/000
5 dave 1/8/001
6 dave 1/10/003
7 kevin 1/2/000
8 kevin 1/3/001
9 kevin 1/4/002
BTW: You really *shouldn't* call your data "data". See:
fortune("dog")
cheers,
Rolf Turner
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and provide commented, minimal, self-contained, reproducible code.
[R] Calculating number of elapsed days from starting date
Hi
I have data for events in rows, with columns for person and date. Each
person may have more than one event;
tC <- textConnection("
Person date
bob 1/1/00
bob 1/2/00
bob 1/3/00
dave1/7/00
dave1/8/00
dave1/10/00
kevin 1/2/00
kevin 1/3/00
kevin 1/4/00
")
data <- read.table(header=TRUE, tC)
close.connection(tC)
rm(tC)
I would like to add a new column to my dataframe containing the calculated
number of elapsed days from the starting date for each person. So the new
dataframe would read
Person dateDays
bob 1/1/00 0
bob 1/2/00 1
bob 1/3/00 2
dave1/7/00 0
dave1/8/00 1
dave1/10/00 3
kevin 1/2/00 0
kevin 1/3/00 1
kevin 1/4/00 2
Not sure how to do this, tried looking through the forum but didn't find
anything that seemed to apply. Suggestions appreciated.
--
View this message in context:
http://r.789695.n4.nabble.com/Calculating-number-of-elapsed-days-from-starting-date-tp4644333.html
Sent from the R help mailing list archive at Nabble.com.
__
R-help@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.
