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$new <- with(dat, ave(flag, Year, FUN=function(s){ s[s=="-"] <- NA;
zoo::na.locf(s) }) )
Error in `[<-.factor`(`*tmp*`, i, value = integer(0)) :
replacement has length zero
On Sat, Feb 25, 2017 at 5:43 PM, David Winsemius <dwinsem...@comcast.net> wrote:
>
>> On Feb 25, 2017, at 10:45 AM, Ashta <sewa...@gmail.com> wrote:
>>
>> Thank you David.
>> is it not possible to sort it by year and flag so that we can make '-'
>> in the second row ? like this for that particular year.
>>
>> 2003 2 Z
>> 2003 1 -
>>
>
> I was a bit surprised by the results of htis since I had assumed than an
> initial NA in a group would remain so, but apparently not:
>
> dat$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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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
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