> On Feb 25, 2017, at 10:45 AM, Ashta <sewa...@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
> <dwinsem...@comcast.net> wrote:
>>
>>> On Feb 25, 2017, at 8:09 AM, Ashta <sewa...@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.
>>
>>
>>> ______________________________________________
>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> David Winsemius
>> Alameda, CA, USA
>>
David Winsemius
Alameda, CA, USA
______________________________________________
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