Slicing of List in Python

Slicing allows us to extract a sub-list (a portion of list items) by specifying a range of indices. It uses the start:end:step notation.

Syntax list[start:end:step]

start → index where the slice begins (inclusive). Default = 0.
end → index where the slice stops (exclusive). Default = len(list).
step → difference between indices (skip value). Default = 1.

Example:

Python

# Example list
numbers = [10, 20, 30, 40, 50, 60, 70, 80]

# 1. Basic slicing
print(numbers[2:5])     # [30, 40, 50] → elements from index 2 to 4

# 2. Omitting start index
print(numbers[:4])      # [10, 20, 30, 40] → from beginning to index 3

# 3. Omitting end index
print(numbers[3:])      # [40, 50, 60, 70, 80] → from index 3 to end

# 4. Using step
print(numbers[1:7:2])   # [20, 40, 60] → every 2nd element between 1 and 6

# 5. Negative indices
print(numbers[-4:])     # [50, 60, 70, 80] → last 4 elements

# 6. Reverse slicing
print(numbers[::-1])    # [80, 70, 60, 50, 40, 30, 20, 10] → reversed list

# 7. Slice with negative step
print(numbers[7:2:-2])  # [80, 60, 40] → from index 7 to 3, skipping backwards

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