I am trying to define a grid in R using the "expand.grid" command:

```
random_1 <- seq(80,100,5)
random_2 <- seq(random_1,120,5)
random_3 <- seq(85,120,5)
random_4 <- seq(random_3,120,5)
split_1 = seq(0,1,0.5)
split_2 = seq(0,1,0.5)
split_3 = seq(0,1,0.5)
DF_2 <- expand.grid(random_1 , random_2, random_3, random_4, split_1, split_2, split_3)
```

But this returns the following error:

```
Error in seq.default(random_3, 120, 5) : 'from' must be of length 1
>
```

Does anyone know how to fix this error?

Thanks