Filling data frame with previous row value

Question

I have a data frame that has 2 columns.

column1 has random numbers in column2 is a place holding column for what i want column3 to look like

  random         


        

Answer 1

Also, unless I'm overlooking something, this seems to work:

DF$state2 <- ave(DF$temp, cumsum(DF$temp), FUN = function(x) x[x != 0])
DF
#       random temp state state2
#1  0.50242337  1.0   1.0    1.0
#2  0.68759406  0.0   1.0    1.0
#3  0.74188374  0.0   1.0    1.0
#4  0.44536403  0.0   1.0    1.0
#5  0.50626137  0.5   0.5    0.5
#6  0.51636498  0.0   0.5    0.5
#7  0.80780471  0.0   0.5    0.5
#8  0.24794844  0.0   0.5    0.5
#9  0.46573337  0.0   0.5    0.5
#10 0.10370515  0.0   0.5    0.5
#11 0.07962587  1.0   1.0    1.0
#12 0.93892894  0.0   1.0    1.0
#13 0.67771302  0.0   1.0    1.0
#14 0.11223162  0.0   1.0    1.0
#15 0.16590718  0.0   1.0    1.0
#16 0.83619527  0.0   1.0    1.0
#17 0.38771300  1.0   1.0    1.0
#18 0.14773708  0.0   1.0    1.0
#19 0.43928154  0.5   0.5    0.5
#20 0.08901350  0.0   0.5    0.5
#21 0.84174743  0.0   0.5    0.5
#22 0.93173871  0.0   0.5    0.5
#23 0.80795517  1.0   1.0    1.0