update

src/util.jl

@@ -6,7 +6,7 @@ export timedifference, showstracktrace, findHighestIndexKey, uuid4snakecase, rep
         dfToString, dataframe_to_json_list, dictToString, dictToString_noKey, 
         dictToString_numbering, extract_triple_backtick_text, 
         countGivenWords, remove_french_accents, detect_keyword, extractTextBetweenCharacter,
-        convertCamelSnakeKebabCase, fitrange, lastElementsIndex
+        convertCamelSnakeKebabCase, fitrange, recentElementsIndex, nonRecentElementsIndex
 
 using JSON3, DataStructures, Distributions, Random, Dates, UUIDs, MQTTClient, DataFrames
 
@@ -1182,32 +1182,75 @@ end
 """ Find a unit range for a vector given a number of the most recent elements of interest.
 
 # Arguments
-  - `v::AbstractVector`
-    the input vector to extract recent elements from
+  - `vectorLength::Integer`
+    the length of the vector to generate range from
   - `n::Integer`
-    the number of most recent elements to include in the range
+    the number of most recent elements to include in range
+
 
 # Return
   - `UnitRange`
-    a range representing the last `n` elements of the vector
+    a range representing the n most recent elements of a vector with length vectorLength
 
 # Example
 ```jldoctest
 julia> a = [1, 2, 3, 4, 5]
-julia> lastElementsIndex(a, 3)
+julia> recentElementsIndex(length(a), 3)
 3:5
+julia> recentElementsIndex(length(a), 0)
+5:5
 ```
 """
-function lastElementsIndex(v::AbstractVector, n::Integer)
-  len = length(v)
+function recentElementsIndex(vectorlength::Integer, n::Integer)
   if n == 0
-    return 1:len
+    error("n must be greater than 0")
   end
   
-  start = max(1, len - n + 1)
-  return start:len
+  start = max(1, vectorlength - n + 1)
+  return start:vectorlength
+end
+
+
+""" Find a unit range for a vector excluding the most recent elements.
+
+# Arguments
+    - `vectorlength::Integer`
+      the length of the vector to generate range from
+    - `n::Integer`
+      the number of most recent elements to exclude from range
+
+# Return
+  - `UnitRange`
+    a range representing the elements of the vector excluding the last `n` elements
+
+# Example
+```jldoctest
+julia> a = [1, 2, 3, 4, 5]
+julia> nonRecentElementsIndex(length(a), 3)
+1:2
+julia> nonRecentElementsIndex(length(a), 1)
+1:4
+julia> nonRecentElementsIndex(length(a), 0)
+1:5
+```
+"""
+function nonRecentElementsIndex(vectorlength::Integer, n::Integer)
+  if n < 0
+      error("n must be non-negative")
+  end
+  if n > vectorlength
+      return 1:0  # empty range
+  end
+  return 1:(vectorlength-n)
 end
 
 
 
+
+
+
+
+
+
+
 end # module util

test/runtests.jl

@@ -1,14 +1,15 @@
 using Test
 using GeneralUtils
 
-@testset "lastElementsIndex" begin
-  @test GeneralUtils.lastElementsIndex([1,2,3,4,5], 3) == 3:5
-  @test GeneralUtils.lastElementsIndex([1,2,3], 5) == 1:3
-  @test GeneralUtils.lastElementsIndex([1], 1) == 1:1
-  @test GeneralUtils.lastElementsIndex(collect(1:10), 4) == 7:10
-  @test GeneralUtils.lastElementsIndex(Float64[], 2) == 1:0
-  @test GeneralUtils.lastElementsIndex([1,2,3], 0) == length([1,2,3])+1:length([1,2,3])
-  @test GeneralUtils.lastElementsIndex(["a","b","c"], 2) == 2:3
+@testset "ealierElementsIndex" begin
+  @test GeneralUtils.ealierElementsIndex([1,2,3,4,5], 2) == 1:3
+  @test GeneralUtils.ealierElementsIndex([1,2,3], 0) == 1:3
+  @test GeneralUtils.ealierElementsIndex([1], 1) == 1:0
+  @test GeneralUtils.ealierElementsIndex([], 0) == 1:0
+  @test GeneralUtils.ealierElementsIndex([1,2,3,4], 4) == 1:0
+  @test GeneralUtils.ealierElementsIndex([1,2,3,4], 5) == 1:0
+  @test GeneralUtils.ealierElementsIndex(collect(1:10), 3) == 1:7
+  @test_throws ErrorException GeneralUtils.ealierElementsIndex([1,2,3], -1)
 end