especially for the time point with midnight time 24:00:00 in R.

data = structure(list(id = c(1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L, 1544L,
1544L, 1544L, 1544L, 1544L, 1544L), study = c(1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L,
1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L, 1502L), patient = c(801L,
801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L,
801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L,
801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L,
801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L,
801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L,
801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L, 801L,
801L, 801L, 801L, 801L, 801L, 801L, 801L), date = c("6/9/2003",
"6/9/2003", "6/9/2003", "6/9/2003", "6/9/2003", "6/9/2003", "6/9/2003",
"6/9/2003", "6/9/2003", "6/9/2003", "6/9/2003", "6/9/2003", "6/9/2003",
"6/10/2003", "6/10/2003", "6/10/2003", "6/16/2003", "6/16/2003",
"6/16/2003", "6/16/2003", "6/16/2003", "6/16/2003", "6/16/2003",
"6/16/2003", "6/16/2003", "6/16/2003", "6/16/2003", "6/16/2003",
"6/17/2003", "6/17/2003", "6/17/2003", "6/17/2003", "6/17/2003",
"6/17/2003", "6/17/2003", "6/17/2003", "6/17/2003", "6/17/2003",
"6/17/2003", "6/17/2003", "6/17/2003", "6/17/2003", "6/18/2003",
"6/18/2003", "6/18/2003", "6/18/2003", "6/23/2003", "6/23/2003",
"6/23/2003", "6/23/2003", "6/23/2003", "6/23/2003", "6/23/2003",
"6/23/2003", "6/23/2003", "6/23/2003", "6/24/2003", "6/24/2003",
"6/24/2003", "6/24/2003", "6/27/2003", "6/27/2003", "6/27/2003",
"6/27/2003", "6/27/2003", "6/27/2003", "6/27/2003", "6/27/2003",
"6/27/2003", "6/27/2003", "6/27/2003", "6/28/2003", "6/28/2003",
"6/28/2003"), clocktm = c("8:58", "8:58", "9:30", "10:00", "11:00",
"12:00", "15:05", "17:00", "21:03", "21:03", "22:00", "23:00",
"24:00:00", "3:00", "5:00", "8:57", "8:58", "8:58", "9:30", "10:00",
"11:00", "12:00", "15:00", "17:00", "21:00", "21:00", "22:00",
"23:00", "0:01", "3:00", "5:00", "8:59", "8:59", "8:59", "9:30",
"10:03", "11:00", "12:00", "13:00", "15:00", "16:59", "21:00",
"0:03", "3:00", "5:00", "9:00", "8:58", "8:58", "9:29", "10:00",
"11:00", "12:00", "13:00", "15:00", "16:58", "20:58", "0:02",
"3:00", "5:00", "8:59", "8:59", "8:59", "9:29", "10:00", "11:00",
"12:03", "13:00", "14:58", "17:00", "20:59", "24:00:00", "3:02",
"5:00", "8:59"), hour = c(0, 0, 0.533, 1.033, 2.033, 3.033, 6.117,
8.033, 12.083, 12.083, 13.033, 14.033, 15.033, 18.033, 20.033,
23.983, 168, 168, 168.533, 169.033, 170.033, 171.033, 174.033,
176.033, 180.033, 180.033, 181.033, 182.033, 183.05, 186.033,
188.033, 192.017, 192.017, 192.017, 192.533, 193.083, 194.033,
195.033, 196.033, 198.033, 200.017, 204.033, 207.083, 210.033,
212.033, 216.033, 336, 336, 336.517, 337.033, 338.033, 339.033,
340.033, 342.033, 344, 348, 351.067, 354.033, 356.033, 360.017,
432.017, 432.017, 432.517, 433.033, 434.033, 435.083, 436.033,
438, 440.033, 444.017, 447.033, 450.067, 452.033, 456.017)), .Names = c("id",
"study", "patient", "date", "clocktm", "hour"), class = "data.frame", row.names = c(NA,
-74L))