Use Python’s built-in `min()`

function with the `key`

argument to find the shortest string in a set. Call `min(my_set, key=len)`

to return the shortest string in the set using the built-in `len()`

function to determine the weight of each string—the shortest string has minimum length.

👉 **Recommended Tutorial**: How to Find the Shortest String in a Python List?

Table of Contents

## Problem Formulation

Given a Python set of strings. Find the string with the minimum number of characters—the shortest string in the set.

Here are a few example sets of strings and the desired output:

# {'Alice', 'Bob', 'Pete'} – --> 'Bob' # {'aaa', 'aaaa', 'aa'} – --> 'aa' # {''} – --> '' # {} – --> ''

## Method 1: min() Function with Key Argument Set to len()

Use Python’s built-in `min()`

function with a key argument to find the shortest string in a set like so: `min(s, key=len)`

. This returns the shortest string in the set `s`

using the built-in `len()`

function to determine the weight of each string—the shortest string will be the minimum.

Here’s the code definition of the `get_min_str()`

function that takes a set of strings as input and returns the shortest string in the list or a `ValueError`

if the set is empty.

def get_min_str(my_set): return min(my_set, key=len)

Here’s the output we obtain when running our desired examples:

print(get_min_str({'Alice', 'Bob', 'Pete'})) # 'Bob' print(get_min_str({'aaa', 'aaaa', 'aa'})) # 'aa' print(get_min_str({''})) # ''

If you pass an empty set, Python will raise a `ValueError: min() arg is an empty sequence`

because you cannot pass an empty iterable into the `min()`

function.

print(get_min_str({})) # ValueError: min() arg is an empty sequence

## Method 2: Handling Empty Sets

If you want to return an alternative value in case the set is empty, you can modify the `get_min_str()`

function to include a second optional argument:

def get_min_str(my_set, fallback=''): return min(my_set, key=len) if my_set else fallback print(get_min_str({})) # '' print(get_min_str({}, fallback='EMPTY!!!!!!')) # EMPTY!!!!!!

## Method 3: Not-So-Pythonic with For Loop

A less Pythonic but, for beginner coders, more readable version is the following loop-based solution:

def get_min_str(my_set, fallback=''): if not my_set: return fallback min_str = '' # set is not empty for x in my_set: if len(x) < len(max_str): min_str = x return min_str print(get_min_str({'Alice', 'Bob', 'Pete'})) # 'Bob' print(get_min_str({'aaa', 'aaaa', 'aa'})) # 'aa' print(get_min_str({''})) # '' print(get_min_str({}, fallback='EMPTY!!!!!!')) # EMPTY!!!!!!

## Method 4: Python Min Length of String in Set

To find the ** minimum length** of a string in a given set, use the

`min(my_set, key=len)`

function to obtain the string with the minimum length and then pass this min string into the `len()`

function to obtain the number of characters.**len(min(my_set, key=len))**

Here’s a more detailed example:

def get_min_str_length(my_set): return len(max(my_set, key=len)) print(get_min_str_length({'Alice', 'Bob', 'Pete'})) # 3 print(get_min_str_length({'aaa', 'aaaa', 'aa'})) # 2 print(get_min_str_length({''})) # 0 print(get_min_str_length({})) # ValueError: min() arg is an empty sequence

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👉 **Recommended Tutorial**: How to Get the Maximum String in a Python Set?

While working as a researcher in distributed systems, Dr. Christian Mayer found his love for teaching computer science students.

To help students reach higher levels of Python success, he founded the programming education website Finxter.com. He’s author of the popular programming book Python One-Liners (NoStarch 2020), coauthor of the Coffee Break Python series of self-published books, computer science enthusiast, freelancer, and owner of one of the top 10 largest Python blogs worldwide.

His passions are writing, reading, and coding. But his greatest passion is to serve aspiring coders through Finxter and help them to boost their skills. You can join his free email academy here.