Convert Set to String in Python

In this article, we will discuss how to convert a set to a string in Python. It can done using two ways – 

Method 1: Using str() We will convert a Set into a String in Python using the str() function.

Syntax : str(object, encoding = ’utf-8?, errors = ’strict’) 

Parameters :

• object : The object whose string representation is to be returned.
• encoding : Encoding of the given object.
• errors : Response when decoding fails.

Returns : String version of the given object

Example 1 :

python3

# create a set
s = {'a', 'b', 'c', 'd'}
print("Initially")
print("The datatype of s : " + str(type(s)))
print("Contents of s : ", s)

# convert Set to String
s = str(s)
print("\nAfter the conversion")
print("The datatype of s : " + str(type(s)))
print("Contents of s : " + s)

Output :

Initially
The datatype of s : <class 'set'>
Contents of s :  {'c', 'd', 'a', 'b'}

After the conversion
The datatype of s : <class 'str'>
Contents of s : {'c', 'd', 'a', 'b'}

Example 2 :

python3

# create a set
s = {'g', 'e', 'e', 'k', 's'}
print("Initially")
print("The datatype of s : " + str(type(s)))
print("Contents of s : ", s)

# convert Set to String
s = str(s)
print("\nAfter the conversion")
print("The datatype of s : " + str(type(s)))
print("Contents of s : " + s)

Output :

Initially
The datatype of s : <class 'set'>
Contents of s :  {'k', 'g', 's', 'e'}

After the conversion
The datatype of s : <class 'str'>
Contents of s : {'k', 'g', 's', 'e'}

Method 2: Using Join() The join() method is a string method and returns a string in which the elements of sequence have been joined by str separator. 

Syntax:

string_name.join(iterable) 

python3

# create a set
s = {'a', 'b', 'c', 'd'}
print("Initially")
print("The datatype of s : " + str(type(s)))
print("Contents of s : ", s)

# convert Set to String
S = ', '.join(s)
print("The datatype of s : " + str(type(S)))
print("Contents of s : ", S)

Output:

Initially
The datatype of s : <class 'set'>
Contents of s :  {'c', 'd', 'a', 'b'}
The datatype of s : <class 'str'>
Contents of s :  c, d, a, b

Method 2: Using functools.reduce()

Syntax:

functools.reduce(function, set) 

Approach: 

• Initialize the set. 
• Use reduce function which takes a function and sets it as parameters. 
• The function applies to each item of the set. 
• Function concatenate the items of the set. 

Python

from functools import reduce
# create a set
s = {'a', 'b', 'c', 'd'}
print("Initially")
print("The datatype of s : " + str(type(s)))
print("Contents of s : ", s)

# convert Set to String
S = reduce(lambda a, b : a+', '+b , s)
print("The datatype of s : " + str(type(S)))
print("Contents of s : ", S)

Output:

Initially
The datatype of s : <class 'set'>
Contents of s :  {'a', 'c', 'd', 'b'}
The datatype of s : <class 'str'>
Contents of s :  a, c, d, b

Time complexity: O(N) N is the length of the set over which reduce function iterate.

Space complexity: O(1) Because no extra space is used.