Question

Merry Christmas

I would like to split a long dataframe. The dataframe looks like this

    x<-c('0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00', '2:30:00', '3:00:00',
    '0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00', '2:30:00', '3:00:00', 
    '3:30:00', '4:00:00','0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00',
     '2:30:00', '3:00:00', '0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00',
     '2:30:00', '3:00:00' , '3:30:00', '4:00:00')

    y=seq(1:32)

    data1=data.frame(x,y)

i want to split in such a way that the output looks like

    0:00:00  1  8 17 24  
    0:30:00  2  9 18 25  
    1:00:00  3 10 19 26  
    1:30:00  4 11 20 27  
    2:00:00  5 12 21 28  
    2:30:00  6 13 22 29  
    3:00:00  7 14 23 30  
    3:30:00 NA 15 NA 31  
    4:00:00 NA 16 NA 32  

any ideas or functions that i look into for doing this? I tried using split function, but could not get it done.
Thanks a lot for your help and time.

The below solution by Matthew works best. However if i increase the cycle time for x

    x<-c('0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00', '2:30:00', '3:00:00', '3:30:00',
    '4:00:00', '4:30:00', '5:00:00', '5:30:00', '6:00:00', '6:30:00', '7:00:00', 
    '7:30:00','8:00:00', '8:30:00', '9:00:00', '9:30:00', '10:00:00', '10:30:00',
     '11:00:00','11:30:00','0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00', '2:30:00', 
    '3:00:00', '3:30:00', '4:00:00', '4:30:00', '5:00:00', '5:30:00', '6:00:00', '6:30:00', 
    '7:00:00', '7:30:00','8:00:00', '8:30:00', '9:00:00', '9:30:00', '10:00:00', '10:30:00', 
    '11:00:00','11:30:00', '12:00:00', '12:30:00', '13:00:00', '13:30:00')

and use the same code, i get the following error:

    Error in match.names(clabs, names(xi)) : names do not match previous names

Cheers,
Swagath

Answer 1

If we can assume that each new cycle starts at 0:00:00 and that each new cycle will always include a 0:00:00, then we can easily use reshape() after creating a “time” variable using cumsum().

data1 <- data.frame(
  x = c('0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00', '2:30:00', 
        '3:00:00', '0:00:00', '0:30:00', '1:00:00', '1:30:00', '2:00:00', 
        '2:30:00', '3:00:00', '3:30:00', '4:00:00','0:00:00', '0:30:00', 
        '1:00:00', '1:30:00', '2:00:00', '2:30:00', '3:00:00', '0:00:00', 
        '0:30:00', '1:00:00', '1:30:00', '2:00:00', '2:30:00', '3:00:00' ,
        '3:30:00', '4:00:00'),
  y = seq(1:32))
data1$times <- cumsum(data1$x == "0:00:00")
reshape(data1, direction = "wide", idvar = "x", timevar = "times")
#          x y.1 y.2 y.3 y.4
# 1  0:00:00   1   8  17  24
# 2  0:30:00   2   9  18  25
# 3  1:00:00   3  10  19  26
# 4  1:30:00   4  11  20  27
# 5  2:00:00   5  12  21  28
# 6  2:30:00   6  13  22  29
# 7  3:00:00   7  14  23  30
# 15 3:30:00  NA  15  NA  31
# 16 4:00:00  NA  16  NA  32