---
title: "Explain Python’s with statement (context manager)."  
description: "Explain Python’s with statement (context manager)."  
author: "Ravi Vishwakarma"  
published: 2025-09-01  
updated: 2025-09-01  
canonical: https://www.mindstick.com/interview/34364/explain-python-s-with-statement-context-manager  
category: "python"  
tags: ["python-3.4", "python", "Python 3"]  
reading_time: 3 minutes  

---

# Explain Python’s with statement (context manager).

#### Explanation

- The `with` statement in Python is used to wrap the execution of a block of code within methods defined by a **context manager**.
- A **context manager** is any object that defines two special methods:

   - `__enter__()` → executed when entering the context (before the block starts).
   - `__exit__()` → executed when exiting the context (after the block ends, even if an error occurs).

- This pattern is mainly used for **resource management** (files, DB connections, sockets, locks, etc.) where resources must be **acquired and released properly**.

#### Common Example (File Handling)

```python
with open("file_name.txt", "w") as f:
    f.write("Hello, World in file_name!")
# File is automatically closed, even if an exception occurs
```

Same as (Handle by **try-catch-finally** statement):

```python
f = open("file_name.txt", "w")
try:
    f.write("Hello, World in file_name!")
finally:
    f.close()  # ensures cleanup
```

#### Custom Example (Creating a Context Manager)

```python
class new_with_MyContext:
    def __enter__(self):
        print("Entering context")
        return "Resource Ready"

    def __exit__(self, exc_type, exc_value, traceback):
        print("Exiting context")
        if exc_type:
            print(f"Handled exception: {exc_value}")
        return True  # suppress exception if needed

# Usage
with new_with_MyContext() as resource:
    print(resource)      # "Resource Ready"
    raise ValueError("Oops!")  # handled inside __exit__
```

## Output:

```plaintext
Entering context
Resource Ready
Exiting context
Handled exception: Oops!
```

## Key Points to Mention in an Interview

1. `with` ensures deterministic cleanup of resources.
2. Avoids boilerplate `try...finally`.
3. Works with files, locks, sockets, DB connections, etc.
4. Can define your own context managers with `__enter__` / `__exit__` or use `contextlib.contextmanager`.

## Answers

### Answer by Ravi Vishwakarma

#### Explanation

- The `with` statement in Python is used to wrap the execution of a block of code within methods defined by a **context manager**.
- A **context manager** is any object that defines two special methods:

   - `__enter__()` → executed when entering the context (before the block starts).
   - `__exit__()` → executed when exiting the context (after the block ends, even if an error occurs).

- This pattern is mainly used for **resource management** (files, DB connections, sockets, locks, etc.) where resources must be **acquired and released properly**.

#### Common Example (File Handling)

```python
with open("file_name.txt", "w") as f:
    f.write("Hello, World in file_name!")
# File is automatically closed, even if an exception occurs
```

Same as (Handle by **try-catch-finally** statement):

```python
f = open("file_name.txt", "w")
try:
    f.write("Hello, World in file_name!")
finally:
    f.close()  # ensures cleanup
```

#### Custom Example (Creating a Context Manager)

```python
class new_with_MyContext:
    def __enter__(self):
        print("Entering context")
        return "Resource Ready"

    def __exit__(self, exc_type, exc_value, traceback):
        print("Exiting context")
        if exc_type:
            print(f"Handled exception: {exc_value}")
        return True  # suppress exception if needed

# Usage
with new_with_MyContext() as resource:
    print(resource)      # "Resource Ready"
    raise ValueError("Oops!")  # handled inside __exit__
```

## Output:

```plaintext
Entering context
Resource Ready
Exiting context
Handled exception: Oops!
```

## Key Points to Mention in an Interview

1. `with` ensures deterministic cleanup of resources.
2. Avoids boilerplate `try...finally`.
3. Works with files, locks, sockets, DB connections, etc.
4. Can define your own context managers with `__enter__` / `__exit__` or use `contextlib.contextmanager`.


---

Original Source: https://www.mindstick.com/interview/34364/explain-python-s-with-statement-context-manager

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