Repeat
Thank you so much David!
But if all element of a group has '-' did not work. In this case year
2006 an example
If all values of flag are '-' within year then I wan to set as N
dat=read.table(text = "Year month flag
2001 1 Z
2001 2 -
2001 4 X
2002 1 Z
2002 2 -
2003 1 -
2003 2 Z
2004 2 Z
2005 3 Z
2005 2 -
2005 3 -
2006 1 -
2006 2 - ", header = TRUE)
dat$new <- with(dat, ave(flag, Year, FUN=function(s){ s[s=="-"] <- NA;
zoo::na.locf(s) }) )
Error in `[<-.factor`(`*tmp*`, i, value = integer(0)) :
replacement has length zero
On Sat, Feb 25, 2017 at 5:43 PM, David Winsemius <dwinsemius at comcast.net> wrote:
On Feb 25, 2017, at 10:45 AM, Ashta <sewashm at gmail.com> wrote: Thank you David. is it not possible to sort it by year and flag so that we can make '-' in the second row ? like this for that particular year. 2003 2 Z 2003 1 -
I was a bit surprised by the results of htis since I had assumed than an initial NA in a group would remain so, but apparently not:
dat$new <- with(dat, ave(flag, Year, FUN=function(s){ s[s=="-"] <- NA; zoo::na.locf(s) }) )
dat
Year month flag new 1 2001 1 Z Z 2 2001 2 - Z 3 2001 4 X X 4 2002 1 Z Z 5 2002 2 - Z 6 2003 1 - Z 7 2003 2 Z Z 8 2004 2 Z Z 9 2005 3 Z Z 10 2005 2 - Z 11 2005 3 - Z David.
On Sat, Feb 25, 2017 at 12:14 PM, David Winsemius <dwinsemius at comcast.net> wrote:
On Feb 25, 2017, at 8:09 AM, Ashta <sewashm at gmail.com> wrote: I have a data set and I want to repeat a column value based on other column value, my data look like read.table(text = "Year month flag 2001 1 Z 2001 2 - 2001 4 X 2002 1 Z 2002 2 - 2003 1 - 2003 2 Z 2004 2 Z 2005 3 Z 2005 2 - 2005 3 -", header = TRUE) Within year If flag = '-' then i want replace '-' by the previous row value of flag. In this example for yea 2001 in month 2 flag is '-' and I want replace it by the previous value of flag (i.e., 'Z') 2001 1 Z 2001 2 Z 2001 4 X If all values of flag are '-' within year then I wan to set as N The complete out put result will be year month flag 2001 1 Z 2001 2 z 2001 4 X 2002 1 Z 2002 2 Z 2003 1 Z 2003 2 Z 2004 2 Z 2005 3 Z 2005 2 N 2005 3 N Thank you in advance
Your example doesn't actually match your verbal description of the algorithm because you have not specified the rule that establishes values for instances where the first value in a year is "-". The `na.locf` function in the 'zoo' package would be useful for the task describe in your verbal description when used in conjunction with the 'stats'-package's `ave` function. -- David.
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David Winsemius Alameda, CA, USA
David Winsemius Alameda, CA, USA