merge list python code example

Example 1: Merge Sort python

def merge_sort(arr):
    # The last array split
    if len(arr) <= 1:
        return arr
    mid = len(arr) // 2
    # Perform merge_sort recursively on both halves
    left, right = merge_sort(arr[:mid]), merge_sort(arr[mid:])

    # Merge each side together
    return merge(left, right, arr.copy())


def merge(left, right, merged):

    left_cursor, right_cursor = 0, 0
    while left_cursor < len(left) and right_cursor < len(right):
      
        # Sort each one and place into the result
        if left[left_cursor] <= right[right_cursor]:
            merged[left_cursor+right_cursor]=left[left_cursor]
            left_cursor += 1
        else:
            merged[left_cursor + right_cursor] = right[right_cursor]
            right_cursor += 1
            
    for left_cursor in range(left_cursor, len(left)):
        merged[left_cursor + right_cursor] = left[left_cursor]
        
    for right_cursor in range(right_cursor, len(right)):
        merged[left_cursor + right_cursor] = right[right_cursor]

    return merged

Example 2: merge sort in python

def mergeSort(myList):
    if len(myList) > 1:
        mid = len(myList) // 2
        left = myList[:mid]
        right = myList[mid:]

        # Recursive call on each half
        mergeSort(left)
        mergeSort(right)

        # Two iterators for traversing the two halves
        i = 0
        j = 0
        
        # Iterator for the main list
        k = 0
        
        while i < len(left) and j < len(right):
            if left[i] < right[j]:
              # The value from the left half has been used
              myList[k] = left[i]
              # Move the iterator forward
              i += 1
            else:
                myList[k] = right[j]
                j += 1
            # Move to the next slot
            k += 1

        # For all the remaining values
        while i < len(left):
            myList[k] = left[i]
            i += 1
            k += 1

        while j < len(right):
            myList[k]=right[j]
            j += 1
            k += 1

myList = [54,26,93,17,77,31,44,55,20]
mergeSort(myList)
print(myList)

Example 3: python how to add one list to another list

# Basic syntax:
first_list.append(second_list) # Append adds the the second_list as an
#	element to the first_list
first_list.extend(second_list) # Extend combines the elements of the 
#	first_list and the second_list

# Note, both append and extend modify the first_list in place

# Example usage for append:
first_list = [1, 2, 3, 4, 5]
second_list = [6, 7, 8, 9]
first_list.append(second_list)
print(first_list)
--> [1, 2, 3, 4, 5, [6, 7, 8, 9]]

# Example usage for extend:
first_list = [1, 2, 3, 4, 5]
second_list = [6, 7, 8, 9]
first_list.extend(second_list)
print(first_list)
--> [1, 2, 3, 4, 5, 6, 7, 8, 9]

Example 4: add two list in python

list1 = ["a", "b" , "c"]
list2 = [1, 2, 3]

list1.extend(list2)
print(list1)

Example 5: append two list of number to one python

listone = [1,2,3]
listtwo = [4,5,6]
mergedlist = []
mergedlist.extend(listone)
mergedlist.extend(listtwo)

Example 6: join lists python

first_list = ["1", "2"]
second_list = ["3", "4"]

# Multiple ways to do this:
first_list += second_list
first_list = first_list + second_list
first_list.extend(second_list)