Data update

Task/Associative-array-Merging/Fortran/associative-array-merging.f

@@ -0,0 +1,94 @@
+module assoc_array_mod
+  implicit none
+  private
+  public :: KeyValue, merge_assoc_arrays
+
+  ! Derived type for key-value pairs
+  type :: KeyValue
+    character(len=:), allocatable :: key
+    character(len=:), allocatable :: value
+  end type KeyValue
+
+contains
+
+  ! Function to merge two associative arrays
+  function merge_assoc_arrays(base, update) result(merged)
+    type(KeyValue), intent(in) :: base(:), update(:)
+    type(KeyValue), allocatable :: merged(:)
+    type(KeyValue), allocatable :: temp(:)
+    integer :: base_size, update_size, i, j, k, merged_size
+    logical :: key_exists
+
+    base_size = size(base)
+    update_size = size(update)
+
+    ! Allocate temporary array to hold all possible keys (worst case: no overlap)
+    allocate(temp(base_size + update_size))
+    merged_size = 0
+
+    ! Add all keys from update array (update takes precedence)
+    do i = 1, update_size
+      merged_size = merged_size + 1
+      temp(merged_size)%key = update(i)%key
+      temp(merged_size)%value = update(i)%value
+    end do
+
+    ! Add keys from base array that are not in update
+    do i = 1, base_size
+      key_exists = .false.
+      do j = 1, update_size
+        if (base(i)%key == update(j)%key) then
+          key_exists = .true.
+          exit
+        end if
+      end do
+      if (.not. key_exists) then
+        merged_size = merged_size + 1
+        temp(merged_size)%key = base(i)%key
+        temp(merged_size)%value = base(i)%value
+      end if
+    end do
+
+    ! Allocate merged array with exact size
+    allocate(merged(merged_size))
+    do i = 1, merged_size
+      merged(i)%key = temp(i)%key
+      merged(i)%value = temp(i)%value
+    end do
+
+    ! Clean up temporary array
+    deallocate(temp)
+  end function merge_assoc_arrays
+
+end module assoc_array_mod
+
+program main
+  use assoc_array_mod
+  implicit none
+  type(KeyValue), allocatable :: base(:), update(:), merged(:)
+  integer :: i
+
+  ! Initialize base associative array
+  allocate(base(3))
+  base(1) = KeyValue("name", "Rocket Skates")
+  base(2) = KeyValue("price", "12.75")
+  base(3) = KeyValue("color", "yellow")
+
+  ! Initialize update associative array
+  allocate(update(3))
+  update(1) = KeyValue("price", "15.25")
+  update(2) = KeyValue("color", "red")
+  update(3) = KeyValue("year", "1974")
+
+  ! Merge the arrays
+  merged = merge_assoc_arrays(base, update)
+
+  ! Print the merged array
+  print *, "Merged associative array:"
+  do i = 1, size(merged)
+    print *, "Key: ", merged(i)%key, ", Value: ", merged(i)%value
+  end do
+
+  ! Clean up
+  deallocate(base, update, merged)
+end program main