rth_element

 syntax

• rth_element(a, b) 
• rth_element(a, b, partioning)

 defintion

1. rth_element(a, b) results in a parameter with the b * n^th element of the ascending sorted data item a (n = number of elements).
2. rth_element(a, b, partioning) results in an attribute the b * n^th elements of the ascending sorted data item a, grouped by the partioning attribute (n = number of elements). The domain unit of the resulting attribute is the values unit of the partioning attribute.

The values unit of the resulting data item should match with regard to value type and metric with the values unit of attribute a.

description

If attribute a has an even number of elements, item b * n does not refer to a unique value. In these cases the mean of the two nearest values is calculated.
If for argument b the value 0.5 is chosen, the function results in the median of attribute a.

applies to

attribute a with value types:

• group: Numeric
• uint2
• uint4
• bool

conditions

Attributes a, b and partioning need to match with regard to their domain unit (for this reason the const function is used in the second expression).

since version

5.61

1.parameter<uint32> rth_elementNrInh: expr = 
   "rth_element(City/NrInhabitants, float32(0.5))";
   result = 400
2.attribute<float32> rth_elementNrInhRegion (RegionDomain):
 expr = 
   "rth_element("
      " City/NrInhabitants"
      ",const(float32(0.5), City)"
      ",City/RegionNr"
   ")";