我想知道如何獲取date difference
的two column
的data.table
使用lapply
的data.table?R:獲取Data.table中的日期差異
library(data.table)
dt <- fread(" ID Date ME_Mes DOB
A 2017-02-20 0.0000 2016-08-19
B 2017-02-06 2.3030 2016-03-11
C 2017-03-20 0.4135 2016-08-19
D 2017-03-06 0.0480 2016-10-09
E 2017-04-20 2.4445 2016-05-04")
> dt
ID Date ME_Mes DOB
1: A 2017-02-20 0.0000 2016-08-19
2: B 2017-02-06 2.3030 2016-03-11
3: C 2017-03-20 0.4135 2016-08-19
4: D 2017-03-06 0.0480 2016-10-09
5: E 2017-04-20 2.4445 2016-05-04
###I'd like to calculate the difference in weeks for every ID by comparing the DOB-Date.
我厭倦了以下內容:
dt[,lapply(.SD, diff.Date), .SDcols = c(4,2), ID] # but did not work!
dt [,「diff」:= difftime(strptime(dt $ Date,format =「%Y-%m-%d」),strptime(dt $ DOB,format =「%Y-%m-% d「),units =」weeks「)]' – Masoud
@Masoud看起來像值得張貼的答案,但我想我會覆蓋每個col作爲IDate:= first。 – Frank