Eva - 4 months ago 28

R Question

`A=matrix(0,4,2)`

A[1,1]=2

A[1,2]=3

A[2,1]=2

A[2,2]=3

A[3,1]=2

A[3,2]=3

A[4,1]=2

A[4,2]=3

Now I want to pick up row 2,4 and return

`this is odd`

But I don't know how to make a loop to pick up row 2,4

Answer

If I understand your question correctly, you want to display some text and the first element of all odd rows. You can try this:

```
cat(paste("This is odd", A[c(2,4),1], "\n"))
```

No need for a loop there. Should you want to work with a larger matrix, and take all odd rows, you can use `seq(2, nrow(A), by=2)`

instead of `c(2,4)`

.