Hi
r-help-boun...@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 TarragonaCreixell Control I 9
2 42 MB TarragonaCreixell Control I 9
3 42 MB TarragonaCreixell Control I 9
4 42 MB TarragonaCreixell Control I 9
5 42 MB TarragonaCreixell Control I 9
6 42 MB TarragonaCreixell Control I 9
ID_SPECIES WEIGHT SIZE NFAMILIA
1 Spondyliosoma cantharus15.64 10 1Sparidae
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 sargus221.4114 5Sparidae
6 Diplodus annularis 3.47 6 1Sparidae
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 BlenniidaeBothidae Carangidae
Centracanthidae
1 2 11 25
4
Congridae Gadidae Haemulidae Mugilidae
Muraenidae
21 2 25 10
45
Myliobatidae ScombridaeSphyraenidaeSynodontidae
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
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