Python insert()

The insert() method of Python’s collections.deque inserts an element at a specified index within the deque. Unlike append() or appendleft(), which add elements only to the ends, insert() can add an element at any valid position.

While deques are optimized for fast appends and pops at both ends, using insert() in the middle may affect performance because it shifts elements internally.

Syntax

deque.insert(index, element)

Parameters:

• index : The position where the new element will be inserted.
• element : The item to insert into the deque.

Return value:

• None: This method modifies the deque in place.

Example 1: Inserting an Element at a Specific Position

This example demonstrates inserting elements at specific positions within a deque:

from collections import deque

# Create a deque
fruits = deque(["apple", "banana", "cherry"])
print("Original deque:", fruits)

# Insert 'orange' at index 1
fruits.insert(1, "orange")
print("After inserting 'orange' at index 1:", fruits)

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The output of this code is:

Original deque: deque(['apple', 'banana', 'cherry'])
After inserting 'orange' at index 1: deque(['apple', 'orange', 'banana', 'cherry'])

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Example 2: Using Negative Indices and Edge Insertions

This example demonstrates inserting elements at the beginning and end using positive and negative indices:

from collections import deque

colors = deque(["red", "green", "blue"])

# Insert at the beginning
colors.insert(0, "purple")

# Insert at the end using len(colors)
colors.insert(len(colors), "yellow")

# Insert before the last item using negative index
colors.insert(-1, "cyan")

print(colors)

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The output of this code is:

deque(['purple', 'red', 'green', 'blue', 'cyan', 'yellow'])

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Here, the insert() method demonstrates its flexibility that it can insert items anywhere in the deque.

Codebyte Example: How to Use deque.insert() for Dynamic Insertions

In this example, insert() adds elements at various positions in a deque, demonstrating dynamic insertions at the beginning, middle, and end:

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