I am assuming that what you say is NULL is really a character string
"NULL", so try this:
> x
A B
1 2 54
2 5 <NA>
3 8 78
4 4 NULL
5 3 26
6 9 NULL
> str(x)
'data.frame': 6 obs. of 2 variables:
$ A: int 2 5 8 4 3 9
$ B: Factor w/ 4 levels "26","54","78",..: 2 NA 3 4 1 4
> dput(x)
structure(list(A = c(2L, 5L, 8L, 4L, 3L, 9L), B = structure(c(2L,
NA, 3L, 4L, 1L, 4L), .Label = c("26", "54", "78", "NULL"), class =
"factor")), .Names = c("A",
"B"), class = "data.frame", row.names = c(NA, -6L))
> x <- x[order(x$A),]
> x
A B
1 2 54
5 3 26
4 4 NULL
2 5 <NA>
3 8 78
6 9 NULL
> x$B[x$B == "NULL"] <- NA
> x
A B
1 2 54
5 3 26
4 4 <NA>
2 5 <NA>
3 8 78
6 9 <NA>
> require(zoo)
Loading required package: zoo
> x$newB <- na.locf(x$B)
> x
A B newB
1 2 54 54
5 3 26 26
4 4 <NA> 26
2 5 <NA> 26
3 8 78 78
6 9 <NA> 78
>
On Sat, Jul 30, 2011 at 3:58 PM, Jeffrey Joh <johjeff...@hotmail.com> wrote:
>
> Sorry about the last message. I forgot to turn the HTML off.
> I would like to reorder a table by column A, then fill column B with the
> values above it. For example:
> A B
> 2 54
> 5 NA
> 8 78
> 4 NULL
> 3 26
> 9 NULL
>
> First sort by column A:
> A B
> 2 54
> 3 26
> 4 NULL
> 5 NA
> 8 78
> 9 NULL
>
> Then replace null/na values in column B with the value above it:
> A B
> 2 54
> 3 26
> 4 26
> 5 26
> 8 78
> 9 78
>
> Jeff
>
>
>> CC: r-help@r-project.org
>> From: dwinsem...@comcast.net
>> To: johjeff...@hotmail.com
>> Subject: Re: [R] Replacing null values
>> Date: Sat, 30 Jul 2011 11:45:21 -0400
>>
>>
>> On Jul 30, 2011, at 2:25 AM, Jeffrey Joh wrote:
>> >
>> > I would like to reorder a two-column table by column A, then fill
>> > column B with the values above it. For example: Original:A B2
>> > 545 NA8 784 NULL3 269 NULL First sort by column A:A
>> > B2 543 264 NULL5 NA8 789 NULL Then replace
>> > null/na values in column B with the value above it:A
>> > B2 543 264 265 268 789 78 What is the
>> > best way to do this?Jeff
>> > [[alternative HTML version deleted]]
>>
>> The "best way to do this" meaning to get help on _this_ mailing list,
>> is to post in plain text and to post the results of dput() on this
>> "two-column table".
>>
>> All this is explained here:
>> > PLEASE do read the posting guide
>> > http://www.R-project.org/posting-guide.html
>> > and provide commented, minimal, self-contained, reproducible code.
>>
>> --
>>
>> David Winsemius, MD
>> West Hartford, CT
>>
>
> ______________________________________________
> R-help@r-project.org mailing list
> 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.
>
--
Jim Holtman
Data Munger Guru
What is the problem that you are trying to solve?
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
