[R] Repeat

[Ashta]

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.
>>>
>>>
>>>> ______________________________________________
>>>> R-help at 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
>