Convert Set to String in Python

Converting a set to a string in Python means changing a group of unique items into a text format that can be easily read and used. Since sets do not have a fixed order, the output may look different each time. For example, a set {1, 2, 3} can be turned into the string "{1, 2, 3}" or into "{3, 1, 2}" etc.

Let's discuss some of the methods of doing it with examples.

Using str()

The simplest and most direct method to convert a set into a string is using str(). It retains the curly braces {} and represents the set in a human-readable format.

a = {1, 2, 3}

res = str(a)  # direct conversion
print(type(res), res)

<class 'str'> {1, 2, 3}

Using f-string

f-strings (f"{a}") offer a simple and readable way to convert a set to a string. They directly format the set as a string, maintaining its curly braces. This method is useful when quick and concise formatting is needed.

a = {1, 2, 3}

res = f"{a}"
print(type(res), res)

<class 'str'> {1, 2, 3}

Using repr()

repr() function provides an official string representation of the set, including curly braces {}. This method is best suited for debugging and logging purposes since it ensures an exact representation of the set.

a = {1, 2, 3}

res = repr(a)  # Returns official string representation
print(type(res), res)

<class 'str'> {1, 2, 3}

Using join()

join() method is ideal when we want to convert a set into a clean, formatted string without curly braces {}. Since join() only works with strings, we first use map(str, a) to convert all elements to strings before joining them.

a = {1, 2, 3}

res = ", ".join(map(str, a)) 
print(type(res), res)

<class 'str'> 1, 2, 3

Explanation:

• map(str, s) converts each element in the set to a string.
• join() merges all the converted strings into a single string, separated by ','.

Using json.dumps()

json.dumps() is a useful approach when we need a JSON-style string representation of a set. Since sets are not JSON serializable, we first convert the set into a list.

import json
a = {1, 2, 3}

res = json.dumps(list(a))  # Convert set to list, then JSON string
print(type(res), res)

<class 'str'> [1, 2, 3]

Explanation:

• list(a) converts the set a to a list
• json.dumps() formats it as a string similar to a JSON array.