I'm having trouble manipulating some data in R. I have a data frame containing info. relating to customer transactions. I extract the minimum date as follows,
hold <- (lapply(with(train_train, split(date,id)),min)) # minimum date
Giving me the following list:
head(hold)
#$`15994113`
#[1] "2012-03-02"
#
#$`16203579`
#[1] "2012-03-02"
#
#$`17472223`
#[1] "2012-03-22"
What I then want to do is take the date returned for each id, and merge it back to a data frame containing other relevant variables for each id. I attempted to do it as follows;
hold <- as.data.frame(unlist(hold))
hold <- as.data.frame(cbind(row.names(hold),hold[,1]))
names(hold) <- c('id', 'mindate')
transactions.temp <- merge(x = transactions.pro, y = hold, by = 'id')
However, the bind destroys the date format and I can't work out how to get a data structure of 'id' 'mindate' that will enable me to merge this onto my main dataset which looks like this;
> head(transactions.pro)
id totaltransactions totalspend meanspend
1: 100007447 1096 6644.88 6.06284671532847
2: 100017875 348 992.29 2.85140804597701
3: 100051423 646 2771.43 4.29013931888545
4: 1000714152 2370 10509.08 4.43421097046414
5: 1002116097 1233 4158.51 3.37267639902676
6: 1004404618 754 2978.15 3.94980106100796
Any advice you provide will be hugely appreciated. Thanks!
Your cbind is implicitly converting your dates to character because of row.names. Use the data.frame method for cbind to achieve this. Essentially replace:
as.data.frame(cbind(row.names(hold),hold[,1]))
with
cbind.data.frame(row.names(hold), hold[,1])