我想知道如何获取date difference
的two column
的data.table
使用lapply
的data.table?R:获取Data.table中的日期差异
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.
我厌倦了以下内容:
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看起来像值得张贴的答案,但我想我会覆盖每个col作为IDate:= first。 – Frank