Manipulating data.tables https://adelaide.zoom.us/rec/share/cOSnys6_VhHCHnqbjAZ2fRsejc2nUiAIsVC2ygx7uTyrYDzUiYZnBs8yid5ND5ga.xjKn_U_A_rflF-F7?startTime=1661387742000 Passcode: B%9p2QnX