Odp: count of factors
Hi r-help-bounces at r-project.org napsal dne 19.01.2011 09:51:43:
Hello everyone, I have a data set like this:
head( fish_transect)
ID_TRANSECT ID_PROJECT DE_ZONE DE_LOCALITY DE_SECTOR MES
1 42 MB Tarragona Creixell Control I 9
2 42 MB Tarragona Creixell Control I 9
3 42 MB Tarragona Creixell Control I 9
4 42 MB Tarragona Creixell Control I 9
5 42 MB Tarragona Creixell Control I 9
6 42 MB Tarragona Creixell Control I 9
ID_SPECIES WEIGHT SIZE N FAMILIA
1 Spondyliosoma cantharus 15.64 10 1 Sparidae
2 Symphodus melanocercus 11.21 10 1 Labridae
3 Diplodus vulgaris 30.20 10 2 Sparidae
4 Diplodus vulgaris 52.24 12 2 Sparidae
5 Diplodus sargus 221.41 14 5 Sparidae
6 Diplodus annularis 3.47 6 1 Sparidae
The table function of the column FAMILIA gives:
<snip>
I want to add a new column "familia2" where those families with low
number
of individuals are listed as "other", that is, for these families Atherinidae Blenniidae Bothidae Carangidae
Centracanthidae
1 2 11 25
4
Congridae Gadidae Haemulidae Mugilidae
Muraenidae
21 2 25 10
45
Myliobatidae Scombridae Sphyraenidae Synodontidae
Torpedinidae
2 1 5 1
1
Trachinidae
1
Use levels make new column fish_transect$familia2 <- fish_transect$familia change levels levels(fish_transect$familia2)[which(table(fish_transect$familia2)<46)]<-"other" You can use any threshold number. Regards Petr BTW you need to have familia as factor not as character variable.
I want them in column "familia2" to be named "others" I've been trying to do a loop telling R to write "others" when the sum
of
FAMILIA was less than 50, but it didn't work because FAMILIA is a
factor,
and there isn't a "count" function (or I didn't find it). I also tried
other
options like the "match" function, "level" function, etc. I know I can
do it
manually typing by myself the names of the 16 families but I want to
learn a
way to do where I don't need to type the names. Thanks in advance! Lucia -- View this message in context:
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