I have a class assignment and need help on the rbind command using a negative 1 in the reference.

I was given an input file which I read in and called it digits.

file is 42000 rows and 700 columns.

I created and populated a vector called digits.0 which has the row number from the input file that matches the selection criteria (in this example ==0).

digits.0 is one column and over 4000 rows.

Once digits.0 is created via the for loop, the next command creates a new vector using rbind with a reference to my input file where the reference uses -1 for a column. What does the -1 do?

```
digits.0<-c(rep(0,4132))
k<-1
for(i in 1:42000){
if(digits[i,1]==0){
digits.0[k]<-i
k<-k+1
}
}
digits.0data<- rbind(digits[digits.0,-1])
```

I would appreciate a quick reply or an online chat if possible.

John2