## S3 method for class 'psp':
marks(x, \dots, dfok=TRUE)           
## S3 method for class 'psp':
marks(x, \dots) <- value"psp").FALSE, data frames of marks are not permitted
    and will generate an error.NULL.marks(x), the result is a vector, factor or data frame,
  containing the mark values attached to the line segments of x.
  If there are no marks, the result is NULL.  For marks(x) <- value, the result is the updated line segment pattern
  x (with the side-effect that the dataset x is updated in
  the current environment).
x.
  They are methods for the generic functions
  marks and marks<-
  for the class "psp" of line segment patterns.
    
  The expression marks(x) extracts the marks of x.
  The assignment marks(x) <- value assigns new marks to the
  dataset x, and updates the dataset x in the current
  environment. 
  
  The marks can be a vector, a factor, or a data frame.
  
  For the assignment marks(x) <- value, the value
  should be a vector or factor of length equal to the number of
  segments in x, or a data frame with as many rows
  as there are segments in x. If value is a single value,
  or a data frame with one row, then it will be replicated
  so that the same marks will be attached to each segment.
  
  To remove marks, use marks(x) <- NULL or unmark(x).psp.object,
  marks,
  marks<-example(psp)
  marks(X) 
  marks(X)[,2]
  marks(X) <- 42
  marks(X) <- NULLRun the code above in your browser using DataLab