copying character data down rows

Question

I have a ridiculous For loop question, and I apologize in advance, but I cannot figure it out. Here is a table:

     Site     Date Software EPFU LABO
3  Site 10 20160517     BCID   70  210
4  Site 10 20160518     BCID   NA   NA
5          20160519     BCID   NA   NA
6          20160520     BCID   NA   NA
7          20160521     BCID   NA   NA
8          20160522     BCID   NA   NA
9  Site 11 20160517     BCID    2  139
10 Site 11 20160518     BCID   NA    9
11         20160519     BCID   NA   NA
12         20160520     BCID   NA   NA
13         20160521     BCID   NA   NA
14         20160522     BCID   NA   NA`

How do I fill the gaps below "Site 10" with text that says "Site 10" until it reaches "Site 11", at which point the cycle repeats with the text "Site 11" and so on...Any help would be appreciated. Site is currently a character class, but I can make it a factor if that will simplify this mess. One additional problem is that the "blank" cells are actually a range of ""," ", and "*"anything that will simplify this mess.

I had (and un-did) the "duplicate" of http://stackoverflow.com/questions/14655286/replace-missing-value-with-previous-value (which is, in essence, @joy's solution below) since you need to do the extra step of turning those blanks into `NA`s before you can just use `na.locf()` — hrbrmstr, Sep 16 '16 at 18:41

Dan Slone · Accepted Answer · 2016-09-16T19:16:57.960

3

This should do it:

library(zoo)
data$Site[data$Site == ""] <- NA
data$Site2 <- na.locf(data$Site,na.rm = FALSE)

edited Sep 16 '16 at 19:16

answered Sep 16 '16 at 18:41

Dan Slone

543
2
8

I had a weird error using that second line, so used the stuff Joy posted and it worked. Just had to make sure all blanks==NA. Thank you! – NoobR Sep 16 '16 at 19:13
1

@NoobR - oops I had a typo. It is fixed now. Thanks for telling me about the error – Dan Slone Sep 16 '16 at 19:17
I dig it. That'll do. Thanks! – NoobR Sep 16 '16 at 19:29

score 2 · Answer 2 · answered Sep 16 '16 at 18:39

2

na.locf() is your friend. It is described as "Generic function for replacing each NA with the most recent non-NA prior to it."

Try:

install.packages("zoo")
df$Site<-zoo::na.locf(df$Site)

answered Sep 16 '16 at 18:39

Joy

769
6
24

copying character data down rows

2 Answers2