I have a data frame 

```
df <- data.frame(x = rep(seq(1:10), 10), y = rep(seq(1:10), each = 10), diameter = rnorm(100, 0.3, 0.03), height = rnorm(100, 0.2, 001))

```

that I want to convert to the `ppp`file by means of the `ppp` of `spatstat` package. I want that the `diameter` and `height` variables are `marks` and I can not do this. I tried f.ex this

```
pp1<-ppp(df$x, df$y,  marks = data.frame(df %>% select(diameter, height)))

```

but does not work. 

The output I want to have is similar to the data file `finepines` that is attached to the `spatstat` package

```
> finpines
Marked planar point pattern: 126 points
Mark variables: diameter, height 
window: rectangle = [-5, 5] x [-8, 2] metres

```