Python del Statement: Deleting Variables and Data Structures

# Delete variable binding from namespace
x = 100
print(x)  # 100

del x
# print(x)  # Raises NameError: name 'x' is not defined

Unlike methods such as list.pop() or dict.pop(), which remove items and return their values, del is a statement that solely performs deletion. When applied to a variable, it removes the name binding from the local or global namespace. If no other references point to the underlying object, Python's garbage collector reclaims its memory. For variable assignments, see Variables, and for list manipulation, review List Methods and list.remove().

1. Syntax and Overview 🔝

del target

The target can be a variable name, a subscription (index/key), or an attribute reference. Multiple targets can also be deleted in a single statement (e.g., del a, b, c).

2. Deleting Variables 🔝

When you delete a variable using del, the variable name is removed from the current namespace. Attempting to access it afterward raises a NameError:

name = "Plus2Net"
print(name)

del name

try:
    print(name)
except NameError as e:
    print("Caught error:", e)

assert 'name' not in locals()

3. Deleting List Items and Slices 🔝

You can remove specific elements from a list by index or delete an entire range of items using slices:

numbers = [10, 20, 30, 40, 50]

# Delete single item by index
del numbers[0]
print(numbers)  # [20, 30, 40, 50]

# Delete slice (remove elements from index 1 to 3)
del numbers[1:3]
print(numbers)  # [20, 50]

assert numbers == [20, 50]

4. Deleting Dictionary Keys 🔝

To remove a key-value pair from a dictionary, pass the key to del:

student = {'id': 1, 'name': 'John', 'mark': 85}

del student['mark']
print(student)  # {'id': 1, 'name': 'John'}

assert 'mark' not in student

Frequently Asked Questions (FAQ) 🔝

Further Reading & Related Tutorials 🔝

• Python Variables & Assignment — Learn how variables and name bindings work in Python.
• Python List Methods — Comprehensive guide to list manipulation, append, pop, and remove.
• Python list.remove() Method — Removing items by value rather than index.
• Python Dictionaries — Key-value storage and dictionary management.
• Python Tutorials Directory — Explore all available Python learning modules.

Practice in Google Colab 🔝

Test variable unbinding, list item deletion, slice removal, and dictionary key clearing in our interactive Google Colab companion notebook:

Interactive Practice: Colab & GitHub

Launch the notebook directly in Google Colab to run live code cells or inspect the source repository on GitHub:

View on GitHub

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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