6.38.7  Testing if an object is in an interval: contains

The contains command determines if an object is in an interval.

• contains takes two arguments:
  • I, an interval.
  • obj, an object.
• contains(I,obj) returns 1 if obj is in I; i.e., either obj is a number which is contained in I or obj is an interval which is a subset of I. It returns 0 otherwise.

Examples.

• Input:
  contains(i[0,2],1)
  Output:

  1

• Input:
  contains(i[0,2],3)
  Output:

  0

• Input:
  contains(i[0,2],i[1,2])
  Output:

  1