Hi,
I need to merge two data sets but I need them to match two columns, not just
one. For example:
Hi,
If 'dat1` and 'dat2` are the two datasets.
merge(dat1,dat2,by=c("plant.species","insect.species"),all=TRUE)
# plant.species insect.species visit.freq no.grains
#1 p.A i.1 5 51
#2 p.A i.2 4 NA
#3 p.A i.3 1 2
#4 p.B i.2 2 21
#5 p.B i.3 10 0
#6 p.C i.1 2 NA
#7 p.C i.4 6 NA
A.K.
Dataset 1, frequency of visits of different insect species to different plant
species. Some plants are visited by more than one species of insects, and
viceversa:
plant.species insect.species visit.freq
p.A i.1 5
p.A i.2 4
p.A i.3 1
p.B i.2 2
p.B i.3 10
p.C i.1 2
p.C i.4 6
Dataset 2, number of pollen grains transferred by the different insect species
for the different plant species
plant.species insect.species no.grains
p.A i.1 51
p.A i.3 2
p.B i.2 21
p.B i.3 0
The datasets are not identical as some plant-insect combinations is in one but
not in the other.
I need to merge both datasets making sure that both columns, "plant.species"
and "insect.species", match.
I have used the merge function before, but only matching by one column, either
plantor insect species, for example. Hope it's clear.
Thanks, Silvia.
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