How to Convert A List into String In Python?

How to Convert A List into String In Python?

List is a data structure in Python that can hold values of different data types. The values are enclosed in square brackets [ ]. Lists are mutable in nature which means their values can be changed. Example of a list is-

list1 = [23,’Apple’,3.5,’Mangoes’]

The values present in a list can be accessed through indexing. For instance, list1[1] will return the value ‘Apple’.

If we would like to take values from a list, perform a mathematical operation on each of them, then it can be done using for loop. The for loop will help us to take each value from the list, perform the desired operation on each element and then append that element into new list.

Strings are basically a sequence of characters that are denoted using inverted commas ‘’. They are immutable in nature which means it cannot be changed once declared. The distinction between two strings can be understood using id().

Examples of a string are-

a=’Bill Gates’

x=’Moscow’

Slicing is the most popular technique that can be performed on strings in Python. It can help us to fetch different characters from a string.

So here we will discuss the ways to convert a list to a string in Python-

1. Using join method
2. Using map()
3. Using list comprehension

So, to begin with let’s see how we can convert list into string using join method-

Let us define a function here that returns a string when a list is passed as a parameter.

Input: [‘Let’s’,’play’,’a’,’game’]

Output: Let’s play a game

 def toString(a):
     str1=" "
     return (str1.join(l1))
 l1=['Lets','play','a','game']
 print(toString(l1)) 

We have made a function called toString here which will take our list as its input then take each of its iterable to join and will return a string.

Here it takes each item from our list l1 and returns the string.

2. Next, let’s see how we can convert a list into string using map () function.

The map function applies a particular functionality to each and every element of list. The syntax for map() function is-

map(function,sequence)

Here we will use str as a function since it converts each element of a list into a string.

And our sequence will be the list l1 = [‘Lets’,’play’,’a’,’game’]

 l1=['Lets','play','a','game']
 toString=' '.join(map(str,l1))
 print(toString) 

In the program given above, we have taken the list l1 and then used the functionality of str on each iterable of our list and then joined them to give our final output.

• In the last approach, we will see how we can use list comprehension to convert a list into string

First, let us see what is list comprehension?

List comprehension provides us a concise way of dealing with our program.

Here we can give an expression for the variables that are present in a sequence.

For instance, the cube of numbers can be calculated using list comprehension in the following way-

 Cubes=[i**3 for j in range(6)]
 print (Cubes) 

Let us understand what will be our approach in the given program-

 l1=['Lets','play','a','game']
 toString=' '.join([str(i) for i in l1])
 print(toString) 

We have taken our list l1 here and then provided the list comprehension where we will take each element from l1 and then convert into string. Finally, we will join all the obtained string to get our desired output.

Let us look at some more examples of map() function and list comprehension here-

Program to merge & print elements of two lists using list comprehension-

print([(a,b) for a in [1,2,3] for b in [4,5,6] if a!=b])

Program using map() function to create a list of squares of numbers in the range 1-10

 def square(a):
       return a*a
 slist=list(map(square,range(1,11))
 print(“Square of numbers from 1-10: “,slist) 

Program to convert strings of uppercase characters into strings of lowercase characters.

 def toLower(str):
     return str.lower()
 l1=[“LETS”,”PLAY”,”A”,”GAME”)
 l2=list(map(toLower,l1))
 print(“List of lowercase characters is: “,l2) 

So in this article, we learned about the three different approaches of converting a list into string; using join method, map() function and list comprehension.

Just deep dive into the world of Python, there are infinite possibilities with the help of functions and their implementations.