On 30.07.2011 21:58, Jeffrey Joh wrote:
Sorry about the last message. I forgot to turn the HTML off.
I would like to reorder a table by column A,
df2 <- df[order(df$A),]
then fill column B with the values above it.
for (i in 1:nrow(df2)) {
if (is.na(df2$B[i]) | df2$B[i] == "NULL") df2$B[i] <- df2$B[i-1]
}
Assumption: <NA> denotes missing value, not a character string "NA".
HTH,
Nik
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
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