MFR - 6 months ago 37

R Question

I wish to know the frequencies that occurred 0. Is there any simple way for that?

`mydf <-data.frame(v1= c("a","b","b","a","b"), v2 =c("l1", "l2","l1","l1","l2"))`

I use this one to see the frequencies of

`v1`

`v2`

`library(plyr)`

count(mydf, c('v1','v2'))

It gives me the following outcome.

`v1 v2 freq`

1 a l1 2

2 b l1 1

3 b l2 2

I wish to have zeros in my output. For instance combination of

`a`

`l2`

`v1 v2 freq`

1 a l1 2

2 b l1 1

3 b l2 2

4 a l2 0

Answer

```
table(mydf$v1, mydf$v2)
l1 l2
a 2 0
b 1 2
as.data.frame(table(mydf$v1, mydf$v2))
Var1 Var2 Freq
1 a l1 2
2 b l1 1
3 a l2 0
4 b l2 2
```