Python String partition() Method

The partition() method in Python is used to split a string into three parts using a specified separator. It always returns a tuple of 3 elements.

Syntax

string.partition(separator)

Parameters:

• separator – The string to search for (must not be empty).

Returns:

• A tuple of 3 parts: (before_separator, separator, after_separator)
• If the separator is not found, the first item will be the entire string, and the second and third will be empty strings.

Example: Basic Usage

text = "python-is-awesome"
result = text.partition("-")
print(result)

('python', '-', 'is-awesome')

Why? Because:

• 'python' comes before the first '-'
• '-' is the separator
• 'is-awesome' comes after

Example: Separator Not Found

text = "learnpython"
result = text.partition(" ")
print(result)

('learnpython', '', '')

The separator (a space) was not found, so the whole string is returned as the first element.

Real-world Use Case

You can use partition() when you want to break a string into 2 parts at the first occurrence of a keyword or symbol. For example:

email = "user@example.com"
username, sep, domain = email.partition("@")
print("Username:", username)
print("Domain:", domain)

Username: user
Domain: example.com

Comparison with split()

• partition() splits at the first occurrence only.
• split() can split multiple times and returns a list.

Common Mistakes

• Using an empty string as the separator → causes a ValueError
• Expecting more than 3 values in the returned tuple

Interview Tip

If you're asked to extract a prefix or postfix around a delimiter in a string, partition() is the fastest and cleanest method to use.

Summary

• partition() splits a string into 3 parts using a separator.
• Returns a tuple: (before, separator, after)
• Helpful for quick parsing and string analysis.

Practice Problem

Write a Python program that reads a string like "title:Introduction to Python" and splits it into label and value using partition().

text = "title:Introduction to Python"
label, sep, value = text.partition(":")
print("Label:", label)
print("Value:", value)

Label: title
Value: Introduction to Python