Mean,Mode,Median (TheAlgorithms#29)

* Average mean

* Average Median

* Average mode

src/TheAlgorithms.jl

@@ -34,6 +34,9 @@ export collatz_sequence
 export euler_method
 export is_armstrong
 export line_length
+export mean
+export median
+export mode
 export SIR # TODO: make the name lowercase if possible
 export surfarea_cube
 export surfarea_sphere
@@ -69,6 +72,9 @@ include("math/abs.jl")
 include("math/area_under_curve.jl")
 include("math/armstrong_number.jl")
 include("math/area.jl")
+include("math/average_mean.jl")
+include("math/average_median.jl")
+include("math/average_mode.jl")
 include("math/ceil_floor.jl")
 include("math/collatz_sequence.jl")
 include("math/euler_method.jl")
@@ -77,6 +83,7 @@ include("math/sir_model.jl")
 
 
 
+
 # Includes: matrix
 include("matrix/lu_decompose.jl") # used by determinant.jl
 include("matrix/determinant.jl")

src/math/average_mean.jl

@@ -0,0 +1,18 @@
+"""
+    mean(nums)
+
+Find mean of a vector of numbers
+
+# Example
+
+```julia
+mean([3, 6, 9, 12, 15, 18, 21])      # returns 12.0
+mean([5, 10, 15, 20, 25, 30, 35])    # returns 20.0
+mean([1, 2, 3, 4, 5, 6, 7, 8])       # returns 4.5
+```
+
+Contributed By:- [Ashwani Rathee](https://github.com/ashwani-rathee)
+"""
+function mean(nums)
+    return sum(nums) / length(nums)
+end

src/math/average_median.jl

@@ -0,0 +1,23 @@
+include("ceil_floor.jl")
+
+"""
+    median(nums)
+
+Finds median of a vector of numbers
+
+# Example
+
+```julia
+median([2,1,3,4])                   # returns 2.5
+median([2, 70, 6, 50, 20, 8, 4])    # returns 8
+median([0])                         # returns 0
+```
+
+Contributed By:- [Ashwani Rathee](https://github.com/ashwani-rathee)
+"""
+function median(nums)
+    sorted = sort(nums)
+    len = length(sorted)
+    mid_index = Int(floor_val(len / 2))
+    return len % 2 == 0 ? (sorted[mid_index+1] + sorted[mid_index]) / 2 : sorted[mid_index+1]
+end

src/math/average_mode.jl

@@ -0,0 +1,43 @@
+"""
+    mode(nums)
+
+Finds mode of a vector of numbers
+
+# Example
+
+```julia
+mode([2, 3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 2, 2, 2])        # returns [2]
+mode([3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 4, 2, 2, 2])        # returns [2]
+mode([3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 4, 4, 2, 2, 4, 2])  # returns [2, 4]
+mode(["x", "y", "y", "z"])                              # returns ["y"]
+mode(["x", "x" , "y", "y", "z"])                       # returns ["x", "y"]
+```
+
+Contributed By:- [Ashwani Rathee](https://github.com/ashwani-rathee)
+"""
+function mode(nums)
+    dict = Dict() # nums => Number of repetitions
+    result = [] # Array of the modes so far
+    max = 0 # Max of repetitions so far
+
+    for i in nums
+        # Add one to the dict[i] entry (create one if none)
+        if i in keys(dict)
+            dict[i] += 1
+        else
+            dict[i] = 1
+        end
+        # Result updated if no of repetitions of i >= max
+        if dict[i] >= max
+            if dict[i] > max
+                empty!(result)
+                max += 1
+            end
+            append!(result, [i])
+        end
+    end
+
+    return result
+end
+println(mode([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]))
+println(mode((1, 1, 2, 4, 4)))

test/math.jl

@@ -1,60 +1,5 @@
 @testset "Math" begin
 
-@testset "Math: Area Under Curve" begin
-    # Area by Trapazoid rule
-    @test trapazoidal_area(x -> 5, 12, 14, 1000) == 10.00000000000334
-	@test trapazoidal_area(x -> 9 * x^2, -4, 0, 1000) == 192.0000960000001
-	@test trapazoidal_area(x -> 9 * x^2, -4, 4, 1000) == 384.0007680000011
-end
-
-@testset "Math: Collatz Sequence" begin
-    @test collatz_sequence(3) == [3,10,5,16,8,4,2,1]
-	@test collatz_sequence(42) == [42,21,64,32,16,8,4,2,1]
-	@test collatz_sequence(5) == [5,16,8,4,2,1]
-end
-
-@testset "Math: Euler Method" begin
-    @test euler_method((x, t) -> x, 1, (0, 5))[1][end] == 143.33937864611195
-end
-
-@testset "Math: Line Length" begin
-    # Arc Lengths
-    @test line_length(x -> x, 0, 1, 10) == 1.4142135623730947
-	@test line_length(x -> 1, -5.5, 4.5) == 9.999999999999977
-	@test line_length(x -> sin(5 * x) + cos(10 * x) + 0.1 * x^2, 0, 10, 10000) == 69.53493003183544
-end
-
-@testset "Math: SIR Model" begin
-    # TODO: implement tests
-
-    #initian conditions
-    p = [0.5/7900000.0,0.33]
-    u0 = [7900000.0,10.0,0.0]
-    tspan = (0.0,140.0)
-
-    #solve
-    sir = ODEProblem(SIR,u0,tspan,p)
-    sol = solve(sir)
-
-    #plot
-    plot(sol)
-end
-
-@testset "Math: Armstrong Number" begin
-    x = 370     # an armstrong number
-    @test is_armstrong(x) == true
-    x = 225     # Not an armstrong number
-    @test is_armstrong(x) == false
-    x = -23     # Not an armstrong number
-    @test is_armstrong(x) == false
-    x = 153     # an armstrong number
-    @test is_armstrong(x) == true
-    x = 0       # an armstrong number
-    @test is_armstrong(x) == true
-    x = 12      # Not an armstrong number
-    @test is_armstrong(x) == false
-end
-
 @testset "Math: abs.jl(Absolute Value) " begin
     @test abs_val(-100) == 100
     @test abs_val(0) == 0
@@ -71,16 +16,12 @@ end
     @test abs_min([-7,-3,6]) == -3
 end
 
-@testset "Math: ceil_floor" begin
-    @test ceil_val(1.3) == 2.0
-    @test ceil_val(2.0) == 2.0
-    @test ceil_val(-1.5) == -1.0
-
-    @test floor_val(1.3) == 1
-    @test floor_val(2.0) == 2.0
-    @test floor_val(-1.7) == -2.0
+@testset "Math: Area Under Curve" begin
+    # Area by Trapazoid rule
+    @test trapazoidal_area(x -> 5, 12, 14, 1000) == 10.00000000000334
+	@test trapazoidal_area(x -> 9 * x^2, -4, 0, 1000) == 192.0000960000001
+	@test trapazoidal_area(x -> 9 * x^2, -4, 4, 1000) == 384.0007680000011
 end
-
 @testset "Math: Area" begin
     @test surfarea_cube(1) == 6
     @test surfarea_cube(3) == 54
@@ -132,4 +73,83 @@ end
     @test_throws DomainError area_rhombus(1,-2)  
     @test_throws DomainError area_rhombus(-1,2)  
 end
+
+@testset "Math: Armstrong Number" begin
+    x = 370     # an armstrong number
+    @test is_armstrong(x) == true
+    x = 225     # Not an armstrong number
+    @test is_armstrong(x) == false
+    x = -23     # Not an armstrong number
+    @test is_armstrong(x) == false
+    x = 153     # an armstrong number
+    @test is_armstrong(x) == true
+    x = 0       # an armstrong number
+    @test is_armstrong(x) == true
+    x = 12      # Not an armstrong number
+    @test is_armstrong(x) == false
+end
+
+@testset "Math: Average Mean" begin
+    @test mean([3, 6, 9, 12, 15, 18, 21]) == 12.0
+    @test mean([5, 10, 15, 20, 25, 30, 35]) == 20.0
+    @test mean([1, 2, 3, 4, 5, 6, 7, 8])  == 4.5
+end
+
+@testset "Math: Average Mode" begin
+    @test mode([2, 3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 2, 2, 2]) == [2]
+    @test mode([3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 4, 2, 2, 2]) == [2]
+    @test mode([3, 4, 5, 3, 4, 2, 5, 2, 2, 4, 4, 4, 2, 2, 4, 2]) == [4, 2]
+    @test mode(["x", "y", "y", "z"]) == ["y"]
+    @test mode(["x", "x" , "y", "y", "z"]) == ["x", "y"]
+end
+
+@testset "Math: Average Median" begin
+    @test median([2,1,3,4]) == 2.5
+    @test median([2, 70, 6, 50, 20, 8, 4]) == 8
+    @test median([0]) == 0
+end
+
+@testset "Math: ceil_floor" begin
+    @test ceil_val(1.3) == 2.0
+    @test ceil_val(2.0) == 2.0
+    @test ceil_val(-1.5) == -1.0
+
+    @test floor_val(1.3) == 1
+    @test floor_val(2.0) == 2.0
+    @test floor_val(-1.7) == -2.0
+end
+
+@testset "Math: Collatz Sequence" begin
+    @test collatz_sequence(3) == [3,10,5,16,8,4,2,1]
+	@test collatz_sequence(42) == [42,21,64,32,16,8,4,2,1]
+	@test collatz_sequence(5) == [5,16,8,4,2,1]
+end
+
+@testset "Math: Euler Method" begin
+    @test euler_method((x, t) -> x, 1, (0, 5))[1][end] == 143.33937864611195
+end
+
+@testset "Math: Line Length" begin
+    # Arc Lengths
+    @test line_length(x -> x, 0, 1, 10) == 1.4142135623730947
+	@test line_length(x -> 1, -5.5, 4.5) == 9.999999999999977
+	@test line_length(x -> sin(5 * x) + cos(10 * x) + 0.1 * x^2, 0, 10, 10000) == 69.53493003183544
+end
+
+@testset "Math: SIR Model" begin
+    # TODO: implement tests
+
+    #initian conditions
+    p = [0.5/7900000.0,0.33]
+    u0 = [7900000.0,10.0,0.0]
+    tspan = (0.0,140.0)
+
+    #solve
+    sir = ODEProblem(SIR,u0,tspan,p)
+    sol = solve(sir)
+
+    #plot
+    plot(sol)
+end
+
 end