ub: Binary search based upper bound operation

In bsearchtools: Binary Search Tools

Description

Returns the index pointing to the first element in the vector that is greater than valueToSearch. The behavior is the same as C++ std::upper_bound function, hence, if the vector is empty it or if valueToSearch is greater than the last element of the vector, it returns length(sortedValues) + 1.

The functions suffixed with the vector type (ubNumeric,ubLogical etc.) can be used ONLY with the specified type, otherwise the vector is coerced, and they are (hopefully negligibly) faster then the generic ub function.

For information about NAs handling see details section.

Usage

ub(sortedValues, valueToSearch)
ubInteger(sortedValues, valueToSearch)
ubNumeric(sortedValues, valueToSearch)
ubLogical(sortedValues, valueToSearch)
ubCharacter(sortedValues, valueToSearch)

Arguments

sortedValues	A sorted atomic vector of type numeric, integer, logical or character
valueToSearch	The value to search. If equal to NA, length(sortedValues)+1 is returned.

Details

ub* functions expect sortedValues to be a vector sorted ascending (duplicated values are allowed). Since the binary search functions rely on values comparison (using < operator) and NA cannot be compared by definition, if sortedValues vector contains NA, the result is unpredictable and NO warning is given. Hence remove them before calling these functions.

Value

The index pointing to the first element in the vector that is not less than (i.e. greater or equal to) valueToSearch.

References

See http://en.cppreference.com/w/cpp/algorithm/lower_bound

Examples

ub(c(1,4,5,5,7,9),5) # returns 5
ub(c(1,4,5,5,7,9),10) # returns 7
ub(numeric(),10) # returns 1

bsearchtools documentation built on May 2, 2019, 8:11 a.m.