how can i sumrows accept a specific values

Question

If I have these data (dat1)

`  L1  L2 L3 L4 L5 L6
   1   0   1  0  4  0  
   4   1   0  1  1  0
   1   0   0  1  4  1

All the values in the matrix are 0,1,4 I need to sum every row ignoring number 4. The result like this

2
3
3

I have more than 900 rows.. I tried these but there is something missing

rowSums(subset(dat1,L1!=4)
rowSums(which[dat1!=4])
n4=dat1[dat1==4]<-0

Answer 1

You could simply do:

dat1[dat1==4] <- 0
rowSums(dat1)

If modifying the object is not acceptable just copy it first:

dat1Zero <- dat1
dat1[dat1Zero==4] <- 0
rowSums(dat1Zero)

Answer 2

If all the values are in (0,1,4) then you just want to count the 1's, no??

apply(df,1,function(x)sum(x==1))
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