Python File Paths

What Is a File Path in Python?

A file path is the address of a file. It tells us where the file is located.

There are two types of paths.

Absolute path — the full address from the root of the file system.

On Windows:

C:\Users\Alex\Documents\file.txt

On Mac or Linux:

/home/alex/documents/file.txt

Relative path — the address relative to where our program is running.

data/file.txt

That means “look in the data folder next to our script.”

Why Do File Paths Matter in Python?

When we open a file, Python needs to know where to find it. If we just write open("file.txt"), Python looks in the current working directory.

If the file is somewhere else, we need to give a path.

The Current Working Directory in Python

The current working directory is the folder where Python is running. We can check it with os.getcwd().

import os

print(os.getcwd())

/home/alex/projects

That tells us where Python is looking when we use a relative path.

How to Open a File with an Absolute Path in Python

We can use an absolute path to open a file.

with open("/home/alex/documents/file.txt", "r") as file:
    content = file.read()

On Windows, we use backslashes. But backslashes are special in Python. So we use raw strings.

with open(r"C:\Users\Alex\Documents\file.txt", "r") as file:
    content = file.read()

The r before the string means “raw string.” It tells Python not to treat backslashes as escape characters.

Or we can use forward slashes. Python handles them on Windows too.

with open("C:/Users/Alex/Documents/file.txt", "r") as file:
    content = file.read()

How to Open a File with a Relative Path in Python

A relative path is relative to the current working directory.

with open("data/file.txt", "r") as file:
    content = file.read()

This looks for a folder called data in the current directory, and then a file called file.txt inside it.

We can also go up a level using ...

with open("../file.txt", "r") as file:
    content = file.read()

That means “go up one folder, then find file.txt.”

How to Join Paths with os.path.join() in Python

Hardcoding paths with slashes is not portable. On Windows, we use backslashes. On Mac and Linux, we use forward slashes.

To make our code work on all systems, we use os.path.join().

import os

folder = "data"
filename = "file.txt"
path = os.path.join(folder, filename)
print(path)

On Windows, the output is:

data\file.txt

On Mac or Linux, the output is:

data/file.txt

So our code works everywhere.

How to Use pathlib for Modern Path Handling in Python

Python 3.4 introduced pathlib. It is a more modern way to work with paths.

from pathlib import Path

path = Path("data") / "file.txt"
print(path)

data/file.txt

pathlib handles paths in an object-oriented way. It works on all systems.

We can check if a file exists.

from pathlib import Path

path = Path("data/file.txt")
if path.exists():
    print("File exists")
else:
    print("File not found")

We can read a file.

from pathlib import Path

path = Path("data/file.txt")
content = path.read_text()
print(content)

We can write to a file.

from pathlib import Path

path = Path("output.txt")
path.write_text("Hello, world!")

pathlib is very convenient. Many Python programmers prefer it over os.path.

Python File Path Example – Reading a File from a Folder

Let’s build a program that reads a file from a specific folder.

import os

folder = "data"
filename = "names.txt"
path = os.path.join(folder, filename)

try:
    with open(path, "r") as file:
        for line in file:
            print(line.strip())
except FileNotFoundError:
    print(f"File not found: {path}")

That is portable and clean.

Another Example – Creating a Folder and Writing a File in Python

import os

folder = "output"
if not os.path.exists(folder):
    os.makedirs(folder)

filepath = os.path.join(folder, "result.txt")
with open(filepath, "w") as file:
    file.write("Hello, world!")

That creates the folder if it does not exist, then writes a file inside it.

Common Mistakes with File Paths in Python

with open("C:\Users\Alex\file.txt", "r") as file:
    content = file.read()

with open(r"C:\Users\Alex\file.txt", "r") as file:
    content = file.read()

with open("C:/Users/Alex/file.txt", "r") as file:
    content = file.read()

with open("file.txt", "r") as file:
    content = file.read()

import os
script_dir = os.path.dirname(os.path.abspath(__file__))
path = os.path.join(script_dir, "file.txt")

with open("data/output.txt", "w") as file:
    file.write("Hello")

import os
os.makedirs("data", exist_ok=True)