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<a class="brand" href="index.html">§10  File Handling</a>

</button>

</div>

<div class="hero-eyebrow">Python Programming Series  ·  Article 10</div>

<h1 class="title">File Handling in Python: A Complete Guide</h1>

Imagine your Python program is a goldfish with a terrible memory. The moment you stop running it, everything it calculated, every user it met, every score it tracked is gone.

<div class="chip"><svg class="icon"><use href="#icon-dial"></use></svg> Every file mode explained</div>

<div class="chip"><svg class="icon"><use href="#icon-grid"></use></svg> CSV & JSON in depth</div>

<div class="chip"><svg class="icon"><use href="#icon-truck"></use></svg> os, pathlib & shutil</div>

<div class="chip"><svg class="icon"><use href="#icon-warn"></use></svg> Real error handling</div>

</div>

</section>

<li><a href="#creating-sample-files-for-this-guide"><svg class="icon"><use href="#icon-file"></use></svg>Creating Sample Files for This Guide</a></li>

<li><a href="#1-opening-a-file"><svg class="icon"><use href="#icon-open"></use></svg>1. Opening a File</a></li>

<li><a href="#2-file-modes-telling-python-what-you-want-to-do"><svg class="icon"><use href="#icon-dial"></use></svg>2. File Modes: Telling Python What You Want to Do</a></li>

<li><a href="#3-closing-a-file"><svg class="icon"><use href="#icon-lockclose"></use></svg>3. Closing a File</a></li>

<li><a href="#4-writing-to-a-file"><svg class="icon"><use href="#icon-pencil"></use></svg>4. Writing to a File</a></li>

<li><a href="#5-reading-from-a-file"><svg class="icon"><use href="#icon-book"></use></svg>5. Reading from a File</a></li>

<li><a href="#6-navigating-inside-a-file-seek-and-tell"><svg class="icon"><use href="#icon-cassette"></use></svg>6. Navigating Inside a File: seek() and tell()</a></li>

<li><a href="#7-file-object-properties"><svg class="icon"><use href="#icon-tag"></use></svg>7. File Object Properties</a></li>

<li><a href="#8-file-and-directory-management-the-os-module"><svg class="icon"><use href="#icon-folder"></use></svg>8. File and Directory Management: The os Module</a></li>

<li><a href="#9-modern-path-handling-pathlib"><svg class="icon"><use href="#icon-path"></use></svg>9. Modern Path Handling: pathlib</a></li>

<li><a href="#10-working-with-csv-files"><svg class="icon"><use href="#icon-grid"></use></svg>10. Working with CSV Files</a></li>

<li><a href="#11-working-with-json-files"><svg class="icon"><use href="#icon-braces"></use></svg>11. Working with JSON Files</a></li>

<li><a href="#12-handling-file-errors-gracefully"><svg class="icon"><use href="#icon-warn"></use></svg>12. Handling File Errors Gracefully</a></li>

<li><a href="#13-copying-and-moving-files-with-shutil"><svg class="icon"><use href="#icon-truck"></use></svg>13. Copying and Moving Files with shutil</a></li>

<li><a href="#your-python-file-handling-cheat-sheet"><svg class="icon"><use href="#icon-grid"></use></svg>Your Python File Handling Cheat Sheet</a></li>

</ul>

</nav>

<hr />

<h2 id="creating-sample-files-for-this-guide"><svg class="icon"><use href="#icon-file"></use></svg>Creating Sample Files for This Guide</h2>

Before diving in, it helps to create a few sample files to use throughout the examples, the same way you'd set up your materials before running an experiment.

os.makedirs("file_handling_demo", exist_ok=True)

with open("file_handling_demo/learn.txt", "w", encoding="utf-8") as f:

f.write("Day 1: Started learning Python file handling!\n")

f.write("Day 2: Understood the 'with' statement. Life changing!\n")

f.write("Day 3: Read and wrote my first CSV file like a data scientist!\n")

print("Sample files created successfully!")

</code></pre></div>

<hr />

<h2 id="1-opening-a-file"><svg class="icon"><use href="#icon-open"></use></svg>1. Opening a File</h2>

Before you can read or write a file, you must open it first, the same way you'd open a book before reading it.

Python's built-in <code>open()</code> function does this job:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>file_object = open(filename, mode, encoding)

</code></pre></div>

<thead>

<tr>

<th>Parameter</th>

<th>Description</th>

<th>Default</th>

</tr>

</thead>

<tbody>

<tr>

<td><code>filename</code></td>

<td>Path to the file (absolute or relative)</td>

<td>Required</td>

</tr>

<tr>

</tr>

<tr>

<td><code>encoding</code></td>

<td>Character encoding to use</td>

<td>Platform-dependent</td>

</tr>

</tbody>

</table></div>

The function returns a file object (also called a file handle).

Worth doing every time: always specify <code>encoding='utf-8'</code> explicitly. The default encoding varies by operating system (Windows tends to use <code>cp1252</code>, Linux and Mac use <code>utf-8</code>). Being explicit makes your code behave the same way on every machine it runs on.

</blockquote>

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>f = open("file_handling_demo/learn.txt", "r", encoding="utf-8")

print("File opened successfully!")

print("Type of file object:", type(f))

f.close()

</code></pre></div>

<div class="output-card"><pre><code>File opened successfully!

Type of file object: <class '_io.TextIOWrapper'>

</code></pre></div>

<hr />

<h2 id="2-file-modes-telling-python-what-you-want-to-do"><svg class="icon"><use href="#icon-dial"></use></svg>2. File Modes: Telling Python What You Want to Do</h2>

The mode is the most important argument after the filename. It tells Python what you plan to do with the file.

Analogy: think of it like booking a table at a restaurant. <code>'r'</code> means you're just reading the menu, no ordering. <code>'w'</code> means you're handed a brand new menu, and the old one gets thrown away. <code>'a'</code> means you want to add new items to the existing menu without touching the rest. <code>'x'</code> means you want to create a new menu, but only if one doesn't already exist.

<h3 id="mode-quick-reference">Mode Quick Reference</h3>

<thead>

<tr>

<th style="text-align: center;">Creates file?</th>

<th style="text-align: center;">Overwrites?</th>

<th style="text-align: center;">Can Write?</th>

</tr>

</thead>

<tbody>

<tr>

</tr>

<tr>

<td>Write</td>

</tr>

<tr>

<td>Append</td>

</tr>

<tr>

<td>Exclusive create</td>

<td style="text-align: center;">✅ (fails if exists)</td>

</tr>

<tr>

<td>Read + Write</td>

</tr>

<tr>

<td>Write + Read</td>

</tr>

<tr>

<td>Append + Read</td>

</tr>

</tbody>

</table></div>

<h3 id="text-vs-binary">Text vs. Binary</h3>

Add <code>'b'</code> to any mode to open in binary mode, for images, videos, audio, or any file that isn't plain text:

- <code>'rb'</code>: read a binary file (like reading a photo)

- <code>'wb'</code>: write a binary file (like saving a downloaded image)

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>f = open("file_handling_demo/learn.txt", "r", encoding="utf-8")

print("'r' readable:", f.readable(), "| writable:", f.writable())

f.close()

f = open("file_handling_demo/temp_w.txt", "w", encoding="utf-8")

print("'w' readable:", f.readable(), "| writable:", f.writable())

f.close()

f = open("file_handling_demo/temp_a.txt", "a", encoding="utf-8")

print("'a' readable:", f.readable(), "| writable:", f.writable())

f.close()

f = open("file_handling_demo/learn.txt", "r+", encoding="utf-8")

print("'r+' readable:", f.readable(), "| writable:", f.writable())

f.close()

try:

f = open("file_handling_demo/brand_new.txt", "x", encoding="utf-8")

f.write("I am a brand new file!\n")

f.close()

print("'x' mode: file created successfully!")

except FileExistsError:

print("'x' mode: file already exists, creation failed (as expected)!")

</code></pre></div>

<div class="output-card"><pre><code>'r' readable: True | writable: False

'w' readable: False | writable: True

'a' readable: False | writable: True

'r+' readable: True | writable: True

'x' mode: file created successfully!

</code></pre></div>

<hr />

<h2 id="3-closing-a-file"><svg class="icon"><use href="#icon-lockclose"></use></svg>3. Closing a File</h2>

When you open a file, the operating system allocates resources to manage it. If you forget to close it, memory is wasted, other programs may not be able to access the file, and data you wrote might not actually be saved yet due to internal buffering.

Analogy: it's like borrowing a book from a library. You're expected to return it, not leave it sitting on your desk forever.

There are three ways to close a file, and they're worth seeing side by side because the last one is genuinely better than the first two.

Method 1: <code>close()</code>, risky. If an error happens before this line runs, the file stays open.

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>f = open("file_handling_demo/learn.txt", "r", encoding="utf-8")

content = f.read()

f.close()

print("File closed:", f.closed)

</code></pre></div>

<div class="output-card"><pre><code>File closed: True

</code></pre></div>

Method 2: <code>try/finally</code>, safer. Guarantees closure even if an error occurs in between.

f = open("file_handling_demo/learn.txt", "r", encoding="utf-8")

content = f.read()

finally:

f.close()

</code></pre></div>

<div class="output-card"><pre><code>File closed: True

</code></pre></div>

Method 3: the <code>with</code> statement, best. Closes the file automatically the moment the block ends, no matter what happens inside it. This is the industry standard, and the one you should default to.

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r", encoding="utf-8") as f:

content = f.read()

# File is automatically closed here, no matter what!

</code></pre></div>

<div class="output-card"><pre><code>File closed: True

</code></pre></div>

Every example from this point on uses <code>with</code>.

<hr />

<h2 id="4-writing-to-a-file"><svg class="icon"><use href="#icon-pencil"></use></svg>4. Writing to a File</h2>

Python gives you two main methods to write data to a file.

<code>write(string)</code> writes a single string to the file and returns the number of characters written. It does not add a newline automatically; you have to include <code>\n</code> yourself. Think of it like typing on a typewriter: you control every character, including the line breaks.

<code>writelines(list_of_strings)</code> writes a list of strings all at once, which is more efficient when you have many lines. It also does not add newlines automatically; each string in the list needs its own <code>\n</code> already included. Think of it like stamping a whole stack of pages in one motion instead of one at a time.

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/shopping_list.txt", "w", encoding="utf-8") as f:

f.write("My Shopping List:\n")

f.write("1. Milk\n")

f.write("2. Eggs\n")

f.write("3. Bread\n")

f.write("4. Coffee (the most important one)\n")

with open("file_handling_demo/shopping_list.txt", "r", encoding="utf-8") as f:

print(f.read())

</code></pre></div>

<div class="output-card"><pre><code>My Shopping List:

1. Milk

2. Eggs

3. Bread

4. Coffee (the most important one)

</code></pre></div>

"Alice's Score: 95\n",

"Bob's Score: 87\n",

"Carol's Score: 92\n",

"Dave's Score: 78\n",

"Eve's Score: 99\n",

]

with open("file_handling_demo/students.txt", "w", encoding="utf-8") as f:

f.write("Student Scores:\n")

f.writelines(students)

with open("file_handling_demo/students.txt", "r", encoding="utf-8") as f:

print(f.read())

</code></pre></div>

<div class="output-card"><pre><code>Student Scores:

Alice's Score: 95

Bob's Score: 87

Carol's Score: 92

Dave's Score: 78

Eve's Score: 99

</code></pre></div>

Switching to <code>'a'</code> mode adds to the end of the file without erasing what's already there:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/shopping_list.txt", "a", encoding="utf-8") as f:

f.write("5. Chocolate\n")

f.write("6. Pizza\n")

print(f.read())

</code></pre></div>

<div class="output-card"><pre><code>My Shopping List:

1. Milk

2. Eggs

3. Bread

4. Coffee (the most important one)

5. Chocolate

6. Pizza

</code></pre></div>

<h3 id="real-world-example-writing-application-logs-like-google">Real-World Example: Writing Application Logs Like Google</h3>

Every major tech company maintains log files, a running record of everything that happens in their systems. Google processes billions of search requests daily, and every error, warning, or event gets written to a log file. Here's a simplified version of that pattern:

def write_log(log_file, level, message):

timestamp = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")

entry = f"[{timestamp}] [{level:7s}] {message}\n"

with open(log_file, "a", encoding="utf-8") as f:

f.write(entry)

log_path = "file_handling_demo/app.log"

write_log(log_path, "INFO", "Server started on port 8080")

write_log(log_path, "INFO", "User 'alice@gmail.com' logged in")

write_log(log_path, "WARNING", "Response time exceeded 500ms for /api/search")

write_log(log_path, "ERROR", "Database connection timeout, retrying...")

write_log(log_path, "INFO", "Database reconnected successfully")

with open(log_path, "r", encoding="utf-8") as f:

print(f.read())

</code></pre></div>

<div class="output-card"><pre><code>[2026-09-02 15:37:34] [INFO ] Server started on port 8080

[2026-09-02 15:37:34] [INFO ] User 'alice@gmail.com' logged in

[2026-09-02 15:37:34] [WARNING] Response time exceeded 500ms for /api/search

[2026-09-02 15:37:34] [ERROR ] Database connection timeout, retrying...

[2026-09-02 15:37:34] [INFO ] Database reconnected successfully

</code></pre></div>

Each call to <code>write_log</code> opens the file in append mode, writes one line, and closes it again, exactly the pattern you'd want for a long-running server that logs events over hours or days.

<hr />

<h2 id="5-reading-from-a-file"><svg class="icon"><use href="#icon-book"></use></svg>5. Reading from a File</h2>

Python offers several ways to read file content, each suited to a different situation:

<thead>

<tr>

<th>Method</th>

<th>Returns</th>

</tr>

</thead>

<tbody>

<tr>

<td>Entire file as one string</td>

<td>File is small, you need everything</td>

</tr>

<tr>

<td>Next <code>n</code> characters</td>

<td>Processing in fixed-size chunks</td>

</tr>

<tr>

<td><code>readline()</code></td>

<td>Next line as a string</td>

<td>Processing line by line with fine control</td>

</tr>

<tr>

<td><code>readlines()</code></td>

<td>All lines as a list</td>

<td>You need every line available as a list</td>

</tr>

<tr>

<td>Lines one at a time</td>

<td>Most common; memory-efficient</td>

</tr>

</tbody>

</table></div>

<code>read()</code> loads the whole file into memory as one string:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r", encoding="utf-8") as f:

content = f.read()

print(content)

</code></pre></div>

<div class="output-card"><pre><code>Day 1: Started learning Python file handling!

Day 2: Understood the 'with' statement. Life changing!

Day 3: Read and wrote my first CSV file like a data scientist!

</code></pre></div>

<code>read(n)</code> reads exactly <code>n</code> characters, and each call picks up exactly where the last one left off:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r", encoding="utf-8") as f:

first_10 = f.read(10)

next_10 = f.read(10)

print(f"First 10 characters: {repr(first_10)}")

print(f"Next 10 characters: {repr(next_10)}")

</code></pre></div>

<div class="output-card"><pre><code>First 10 characters: 'Day 1: Sta'

Next 10 characters: 'rted learn'

</code></pre></div>

<code>readline()</code> reads one line at a time, including the trailing <code>\n</code>, and returns an empty string once it reaches the end of the file:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r", encoding="utf-8") as f:

line1 = f.readline()

line2 = f.readline()

line3 = f.readline()

line4 = f.readline() # Empty string = end of file

print("Line 1:", repr(line1))

print("Line 4 (EOF):", repr(line4))

</code></pre></div>

<div class="output-card"><pre><code>Line 1: 'Day 1: Started learning Python file handling!\n'

Line 4 (EOF): ''

</code></pre></div>

<code>readlines()</code> reads everything and hands it back as a list of lines:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r", encoding="utf-8") as f:

lines = f.readlines()

print("Type:", type(lines))

print("Number of lines:", len(lines))

print("First entry:", lines[0].strip())

print("Last entry:", lines[-1].strip())

</code></pre></div>

Number of lines: 3

First entry: Day 1: Started learning Python file handling!

Last entry: Day 3: Read and wrote my first CSV file like a data scientist!

</code></pre></div>

Looping directly over the file object is the option you'll reach for most often, because it reads one line at a time without ever loading the whole file into memory:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r", encoding="utf-8") as f:

for line_num, line in enumerate(f, 1):

line = line.strip()

if line:

print(f" Entry {line_num}: {line}")

</code></pre></div>

<div class="output-card"><pre><code> Entry 1: Day 1: Started learning Python file handling!

Entry 2: Day 2: Understood the 'with' statement. Life changing!

Entry 3: Day 3: Read and wrote my first CSV file like a data scientist!

</code></pre></div>

Picture a 10 GB server log. <code>read()</code> would try to pull the entire thing into memory at once, which could crash the program. Looping line by line never holds more than one line in memory at a time, which is exactly why it's the default choice for anything that might be large.

<h3 id="real-world-example-reading-user-data-like-netflix">Real-World Example: Reading User Data Like Netflix</h3>

Netflix analyzes watch history to power its recommendation engine, processing lines of history data stored in files. Here's a simplified version:

"alice,Stranger Things,S01E01,45:30,2024-01-15\n",

"alice,Stranger Things,S01E02,50:22,2024-01-15\n",

"alice,The Crown,S01E01,58:10,2024-01-16\n",

"bob,Breaking Bad,S01E01,47:00,2024-01-15\n",

"bob,Breaking Bad,S01E02,48:30,2024-01-16\n",

"carol,Money Heist,S01E01,42:15,2024-01-17\n",

"alice,Breaking Bad,S01E01,47:00,2024-01-17\n",

]

with open("file_handling_demo/watch_history.txt", "w", encoding="utf-8") as f:

f.writelines(watch_history)

user_shows = {}

with open("file_handling_demo/watch_history.txt", "r", encoding="utf-8") as f:

for line in f:

parts = line.strip().split(",")

user, show = parts[0], parts[1]

if user not in user_shows:

user_shows[user] = set()

user_shows[user].add(show)

for user, shows in user_shows.items():

print(f" {user}: {', '.join(sorted(shows))}")

</code></pre></div>

<div class="output-card"><pre><code> alice: Breaking Bad, Stranger Things, The Crown

bob: Breaking Bad

carol: Money Heist

</code></pre></div>

This tiny script is the same basic shape as the first step of a real recommendation system: turn raw event logs into a per-user profile.

<hr />

<h2 id="6-navigating-inside-a-file-seek-and-tell"><svg class="icon"><use href="#icon-cassette"></use></svg>6. Navigating Inside a File: <code>seek()</code> and <code>tell()</code></h2>

When you read from a file, Python tracks your position with an invisible cursor, the same way a text editor tracks the blinking cursor on screen. Every character you read moves it forward.

Analogy: think of a file like a cassette tape. <code>tell()</code> tells you which second of the tape you're currently at. <code>seek()</code> lets you fast-forward or rewind to any point instantly.

<ul>

<li><code>tell()</code>: "Where is the cursor right now?" Returns the current byte position.</li>

<li><code>seek(offset, whence)</code>: "Move the cursor to this position."</li>

</ul>

<thead>

<tr>

<th><code>whence</code> value</th>

<th>Meaning</th>

</tr>

</thead>

<tbody>

<tr>

<td><code>0</code> (default)</td>

<td>From the beginning of the file</td>

</tr>

<tr>

<td>From the current position</td>

</tr>

<tr>

</tr>

</tbody>

</table></div>

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r", encoding="utf-8") as f:

print("Starting position:", f.tell()) # 0 at the beginning

first_line = f.readline()

print("After reading line 1:", f.tell()) # Moved forward!

second_line = f.readline()

print("After reading line 2:", f.tell())

f.seek(0) # Back to the very beginning

print("After seek(0):", f.tell())

line_again = f.readline()

print("Line 1 again:", repr(line_again))

f.seek(7) # Skip "Day 1: " (7 characters)

print("After seek(7):", repr(f.read(8)))

</code></pre></div>

<div class="output-card"><pre><code>Starting position: 0

After reading line 1: 46

After reading line 2: 101

After seek(0): 0

Line 1 again: 'Day 1: Started learning Python file handling!\n'

After seek(7): 'Started '

</code></pre></div>

<hr />

<h2 id="7-file-object-properties"><svg class="icon"><use href="#icon-tag"></use></svg>7. File Object Properties</h2>

Once you open a file, the file object comes with properties that let you inspect its current state:

<thead>

<tr>

<th>Property / Method</th>

<th>Description</th>

</tr>

</thead>

<tbody>

<tr>

</tr>

<tr>

<td>The mode the file was opened in</td>

</tr>

<tr>

<td><code>.closed</code></td>

<td><code>True</code> if the file is closed, <code>False</code> if open</td>

</tr>

<tr>

<td><code>.readable()</code></td>

</tr>

<tr>

<td><code>.writable()</code></td>

<td><code>True</code> if the file can be written to</td>

</tr>

<tr>

<td><code>.seekable()</code></td>

<td><code>True</code> if <code>seek()</code> is supported</td>

</tr>

</tbody>

</table></div>

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/learn.txt", "r+", encoding="utf-8") as f:

print(f" .name : {f.name}")

print(f" .mode : {f.mode}")

print(f" .closed : {f.closed}")

print(f" .readable() : {f.readable()}")

print(f" .writable() : {f.writable()}")

print(f" .seekable() : {f.seekable()}")

print(f"After 'with' block, .closed: {f.closed}")

</code></pre></div>

<div class="output-card"><pre><code> .name : file_handling_demo/learn.txt

.mode : r+

.closed : False

.readable() : True

.writable() : True

.seekable() : True

After 'with' block, .closed: True

</code></pre></div>

<hr />

<h2 id="8-file-and-directory-management-the-os-module"><svg class="icon"><use href="#icon-folder"></use></svg>8. File and Directory Management: The <code>os</code> Module</h2>

The <code>os</code> module is Python's interface to your operating system. It lets you navigate the file system, create and delete directories, and rename or delete files, the same operations you'd normally do by clicking around in File Explorer or Finder, just from code instead.

<h3 id="key-functions-at-a-glance">Key Functions at a Glance</h3>

<thead>

<tr>

<th>Function</th>

</tr>

</thead>

<tbody>

<tr>

<td><code>os.getcwd()</code></td>

<td>Get the current working directory</td>

</tr>

<tr>

<td><code>os.listdir(path)</code></td>

<td>List files and folders</td>

</tr>

<tr>

<td><code>os.mkdir(path)</code></td>

<td>Create one directory</td>

</tr>

<tr>

<td><code>os.makedirs(path)</code></td>

<td>Create a directory plus all missing parent directories</td>

</tr>

<tr>

<td><code>os.rmdir(path)</code></td>

<td>Remove an empty directory</td>

</tr>

<tr>

<td><code>os.rename(src, dst)</code></td>

<td>Rename a file or directory</td>

</tr>

<tr>

<td><code>os.remove(path)</code></td>

<td>Delete a file</td>

</tr>

<tr>

<td><code>os.path.exists(path)</code></td>

<td>Check if a file or folder exists</td>

</tr>

<tr>

<td><code>os.path.isfile(path)</code> / <code>isdir(path)</code></td>

<td>Check whether it's a file or a directory</td>

</tr>

<tr>

<td>Build paths safely, correct on every OS</td>

</tr>

<tr>

<td><code>os.path.getsize(path)</code></td>

<td>Get file size in bytes</td>

</tr>

<tr>

<td><code>os.path.basename(path)</code> / <code>dirname(path)</code></td>

<td>Get just the filename, or just the directory</td>

</tr>

</tbody>

</table></div>

os.mkdir("file_handling_demo/reports")

# makedirs() creates every missing intermediate directory in one call

os.makedirs("file_handling_demo/archive/2026/january", exist_ok=True)

</code></pre></div>

<code>exist_ok=True</code> tells <code>os.makedirs()</code> to do nothing quietly if the directory already exists, instead of raising an error. By default, <code>exist_ok</code> is <code>False</code>, so calling <code>os.makedirs()</code> a second time on a folder that already exists raises <code>FileExistsError</code>:

os.makedirs("file_handling_demo/reports", exist_ok=False)

except FileExistsError as e:

print(f"Confirmed: {e}")

</code></pre></div>

<div class="output-card"><pre><code>Confirmed: [Errno 17] File exists: 'file_handling_demo/reports'

</code></pre></div>

Renaming and deleting work the way you'd expect:

<div class="code-card"><div class="code-head"><div class="dots"></div>python<button class="copy-btn" type="button"><svg class="icon"><use href="#icon-copy"></use></svg>Copy</button></div><pre><code>with open("file_handling_demo/old_name.txt", "w") as f:

f.write("I will be renamed!\n")

os.rename("file_handling_demo/old_name.txt", "file_handling_demo/new_name.txt")

print("Old name exists:", os.path.exists("file_handling_demo/old_name.txt"))

print("New name exists:", os.path.exists("file_handling_demo/new_name.txt"))

if os.path.exists("file_handling_demo/new_name.txt"):

os.remove("file_handling_demo/new_name.txt")

print("File removed safely!")

os.rmdir("file_handling_demo/reports")

print("Empty directory removed!")

</code></pre></div>

<div class="output-card"><pre><code>Old name exists: False

New name exists: True

File removed safely!

Empty directory removed!

</code></pre></div>

<code>os.rmdir()</code> only works on empty directories; if the folder still has files in it, it raises an error. (Section 13 covers <code>shutil.rmtree()</code>, which removes a directory and everything inside it in one call.)

<code>os.path</code> gives you a set of tools for inspecting and building paths without ever hardcoding a separator:

print(f" exists() : {os.path.exists(file_path)}")

print(f" isfile() : {os.path.isfile(file_path)}")

print(f" getsize() : {os.path.getsize(file_path)} bytes")

print(f" basename() : {os.path.basename(file_path)}")

print(f" dirname() : {os.path.dirname(file_path)}")

safe_path = os.path.join("file_handling_demo", "reports", "summary.txt")

print(f"os.path.join(): {safe_path}")

</code></pre></div>

<div class="output-card"><pre><code> exists() : True

isfile() : True

getsize() : 164 bytes

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