[R] If Loop With Lagged Variable

[Rui Barradas]

Hello,

The following might be a better solution.
I include a minimal data set as an example.


Date <- c(rep(as.Date("2018-03-29"), 4),
           rep(as.Date("2018-03-30"), 4),
           rep(as.Date("2018-04-01"), 4))

ari18.test3 <- data.frame(Date)
ari18.test3$GameNum <- 1

#---

d <- c(0, diff(ari18.test3$Date) != 0)
ari18.test3$GameNum <- ari18.test3$GameNum + cumsum(d)

ari18.test3
#         Date GameNum
#1  2018-03-29       1
#2  2018-03-29       1
#3  2018-03-29       1
#4  2018-03-29       1
#5  2018-03-30       2
#6  2018-03-30       2
#7  2018-03-30       2
#8  2018-03-30       2
#9  2018-04-01       3
#10 2018-04-01       3
#11 2018-04-01       3
#12 2018-04-01       3


Hope this helps,

Rui Barradas

Às 22:09 de 19/09/19, Rui Barradas escreveu:
> Hello,
> 
> There was no attachment, R-Help allows only a limited number of file 
> types, see the posting guide and try reposting.
> 
> As for the question, try ifelse, the vectorized fom of if/else.
> 
> ifelse(ari18.test3$Date > lag(ari18.test3$Date), ari18.tesm3$GameNum + 
> 1, ari18.test3$gameNum)
> 
> 
> (Not tested, since there is no data.)
> 
> Hope this helps,
> 
> Rui Barradas
> 
> Às 17:27 de 19/09/19, Phillip Heinrich escreveu:
>> Attached is every at bat for the Arizona Diamondback’s first three 
>> games of 2018 – BBdata1.rda.  I added the Date and DHCode variables by 
>> parsing the first variable labeled GameID.
>>
>> BBdata2 is a reduced dataset with five variables as shown in the str() 
>> command.
>>
>> data.frame':    234 obs. of  5 variables:
>>   $ GameID : Factor w/ 3 levels "ARI201803290",..: 1 1 1 1 1 1 1 1 1 1 
>> ...
>>   $ Date   : Date, format: "2018-03-29" "2018-03-29" "2018-03-29" 
>> "2018-03-29" ...
>>   $ DHCode : Factor w/ 1 level "0": 1 1 1 1 1 1 1 1 1 1 ...
>>   $ GameNum: num  1 1 1 1 1 1 1 1 1 1 ...
>>   $ Date2  : Date, format: NA "2018-03-29" "2018-03-29" "2018-03-29" ...
>>    I’m trying to increment the GameNum (game number) to game 2 when 
>> the date changes from 2018-03-29 to 2018-03-30 in row 81 and to game 3 
>> in row 165.
>>
>> According to my R for Dummies book the following code should work but 
>> it doesn’t.  I keep getting the following error.  Any suggestions?
>>
>> if(ari18.test3$Date > lag(ari18.test3$Date)) {ari18.test3$gameNum <- 
>> ari18.tesm3$GameNum + 1}
>> Warning message:
>> In if (ari18.test3$Date > lag(ari18.test3$Date)) { :
>>    the condition has length > 1 and only the first element will be used
>>              >
>>
>>
>> Thanks.
>> ______________________________________________
>> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>> PLEASE do read the posting guide 
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
> 
> ______________________________________________
> R-help using r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.