CODEWITHSUNDEEP
r
Rinot
Rinot

Reputation: 199

Compare two data frames with different rows using R

I have two data frames with different row numbers: 

class1<-c(1,2,5,6,7)
abund1<-c(10.4,7.5,7.1,5.1,3.2)
df1<-data.frame(class1,abund1)

class2<-c(1,2,3,4,5,6,7)
abund2<-c(9.5,8.4,8,6.3,6,2.4,1.2)
df2<-data.frame(class2,abund2)

I would like to compare these two data frames but I would need the same number of rows. My purpose is to fill by zero all those classes which do not match with the df2. The solution would be as it follows: 

  class abund
     1   10.4
     2    7.5
     3    0.0
     4    0.0
     5    7.1
     6    5.1
     7    3.2

Any ideas? Thank you so much!

Upvotes: 0

Views: 96

Answers (2)

akrun
akrun

Reputation: 886938

An option with data.table

 library(data.table)#v1.9.5+
 setDT(df1, key='class1')[df2][is.na(abund1), abund1:=0][, abund2:=NULL][]
 #   class1 abund1
 #1:      1   10.4
 #2:      2    7.5
 #3:      3    0.0
 #4:      4    0.0
 #5:      5    7.1
 #6:      6    5.1
 #7:      7    3.2

Upvotes: 0

user227710
user227710

Reputation: 3194

kk<-merge(df1,df2,by.x="class1",by.y="class2",all.y=TRUE)[-3]
kk[is.na(kk$abund1),2]<-0
> kk
  class1 abund1
1      1   10.4
2      2    7.5
3      3    0.0
4      4    0.0
5      5    7.1
6      6    5.1
7      7    3.2

Upvotes: 1

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