How to Read Files in Python

So far, every value in your programs has disappeared the moment the program ended. Real programs need to load data that already exists: a guest list, a settings file, a log from a web server. In this lesson, you'll learn how to read files in Python using the built-in open() function, the three main reading methods, and the right way to deal with newlines, encodings and missing files.

What does it mean to read a file in Python?

A text file is just characters saved on your disk, like a .txt, .log or .csv file. Reading a file means copying those characters into your program as a string, so you can print them, search them or do calculations with them.

Reading always takes three steps:

1. Open the file with open(). This gives you a file object, a connection between your program and the file on disk.
2. Read from the file object with a method such as read().
3. Close the file with close() so the operating system can free it.

Our sample file

For the examples below, create a file named guests.txt in the same folder as your Python script, with these four lines:

Alice
Bob
Chloe
Diego

Python looks for the file in the current working directory, which is usually the folder you run your script from. If the file lives somewhere else, give the full path, such as "C:/Users/sam/party/guests.txt" or "/home/sam/party/guests.txt".

How do you open and read a whole file?

The simplest way is read(), which returns the entire file as one string:

file = open("guests.txt", encoding="utf-8")
content = file.read()
file.close()

print(content)

Alice
Bob
Chloe
Diego

The first argument to open() is the file name. The encoding="utf-8" part tells Python how the characters are stored, which we'll come back to shortly.

You can also pass a number to read() to get only that many characters:

file = open("guests.txt", encoding="utf-8")
print(file.read(5))
file.close()

Alice

File modes: "r", "w", "a" and more

The optional second argument of open() is the mode. It tells Python what you plan to do with the file. If you leave it out, Python uses "r" (read), which is why the examples above didn't need it.

This lesson uses "r". The writing modes are covered in How to Write and Append to Files in Python.

How do you read a file line by line?

readline(): one line at a time

Each call to readline() returns the next line, including the newline character \n at the end. We print with repr() here so you can see that hidden character:

file = open("guests.txt", encoding="utf-8")
first = file.readline()
second = file.readline()
file.close()

print(repr(first))
print(repr(second))

'Alice\n'
'Bob\n'

The file object remembers its position, like a bookmark. After reading Alice, the bookmark moves to the start of Bob's line. When the file is finished, readline() returns an empty string "".

readlines(): all lines in a list

file = open("guests.txt", encoding="utf-8")
lines = file.readlines()
file.close()

print(lines)
print(len(lines), "guests")

['Alice\n', 'Bob\n', 'Chloe\n', 'Diego\n']
4 guests

Looping over the file: the best way

A file object works directly in a for loop. Each pass gives you the next line. This is the most common way to read files in Python because it reads one line at a time, so it works even for files bigger than your computer's memory.

file = open("guests.txt", encoding="utf-8")
for line in file:
    print(line)
file.close()

Alice

Bob

Chloe

Diego

Notice the blank lines? Each line already ends with \n, and print() adds another one.

How do you remove the newline from each line?

Use the string method strip(), which removes spaces and newlines from both ends. (rstrip() removes them from the right end only.)

file = open("guests.txt", encoding="utf-8")
for line in file:
    name = line.strip()
    print("Welcome,", name)
file.close()

Welcome, Alice
Welcome, Bob
Welcome, Chloe
Welcome, Diego

Another handy trick: read().splitlines() gives you a list of lines without the \n characters.

file = open("guests.txt", encoding="utf-8")
guests = file.read().splitlines()
file.close()

print(guests)
print("Chloe" in guests)

['Alice', 'Bob', 'Chloe', 'Diego']
True

Comparing read(), readline() and readlines()

Why should you set encoding="utf-8"?

An encoding is the rule that turns bytes on the disk into characters like é, ü, ₹ or emoji. Almost every file today uses UTF-8. If you leave out encoding, Python uses your operating system's default, which on many Windows computers is not UTF-8. A menu that says "Café" can then come out as "Café", or the program can crash with a UnicodeDecodeError.

Writing encoding="utf-8" every time makes your program behave the same on Windows, macOS and Linux.

What happens if the file doesn't exist?

Opening a missing file in read mode raises a FileNotFoundError:

file = open("guest.txt", encoding="utf-8")

FileNotFoundError: [Errno 2] No such file or directory: 'guest.txt'

A typo in the name (guest.txt instead of guests.txt) or running the script from a different folder are the usual causes. You can catch the error with try and except and show a friendly message instead:

try:
    file = open("guest.txt", encoding="utf-8")
    print(file.read())
    file.close()
except FileNotFoundError:
    print("Sorry, the guest list is missing.")

Sorry, the guest list is missing.

Real-world example: finding errors in a server log

Web servers write a line to a log file for everything that happens. Here's a small server.log:

2026-03-01 09:15:02 INFO Server started
2026-03-01 09:17:45 WARNING Disk space at 85%
2026-03-01 09:20:11 ERROR Database connection lost
2026-03-01 09:20:15 INFO Reconnected to database
2026-03-01 09:42:30 ERROR Payment service timeout

This program reads it line by line and reports only the errors:

error_count = 0

log = open("server.log", encoding="utf-8")
for line in log:
    if "ERROR" in line:
        error_count += 1
        time = line.split()[1]
        message = line.split("ERROR ")[1].strip()
        print(f"{time} -> {message}")
log.close()

print("Total errors:", error_count)

09:20:11 -> Database connection lost
09:42:30 -> Payment service timeout
Total errors: 2

Because it loops line by line, the same code works on a log with ten lines or ten million.

Common mistakes when reading files

1. Reading the same file object twice

file = open("guests.txt", encoding="utf-8")
print(len(file.read()))
print(len(file.read()))
file.close()

22
0

After the first read(), the bookmark sits at the end of the file, so the second call returns an empty string. Save the result in a variable and reuse it, or open the file again.

2. Forgetting that lines end with \n

Comparing line == "Bob" is always False, because the line is really "Bob\n". Call line.strip() first.

3. Forgetting that everything you read is a string

Even if a file contains numbers, read() gives you text. Convert with int() or float() before doing math, as you learned in type conversion.

4. Leaving out the encoding

Code that works on your Mac may break on a colleague's Windows laptop. Always pass encoding="utf-8" for text files.

Practice exercise

72
88
95
61

scores = []

file = open("scores.txt", encoding="utf-8")
for line in file:
    scores.append(int(line.strip()))
file.close()

total = sum(scores)
print("Scores:", len(scores))
print("Total:", total)
print("Average:", total / len(scores))

Scores: 4
Total: 316
Average: 79.0

What's next?

You can now load data from any text file. Next, learn to save data: How to Write and Append to Files in Python.