Python program to Concatenate all Elements of a List into a String
Last Updated :
31 Aug, 2022
Given a list, the task is to write a Python program to concatenate all elements in a list into a string i.e. we are given a list of strings and we expect a result as the entire list is concatenated into a single sentence and printed as the output.
Examples:
Input: ['hello', 'geek', 'have', 'a', 'geeky', 'day']
Output: hello geek have a geeky day
Using the Naive approach to concatenate items in a list to a single string
Here, we are taking a list of words, and by using the Python loop we are iterating over each element and concatenating words with the help of the “+” operator.
Python3
l = [ 'hello', 'geek', 'have',
'a', 'geeky', 'day']
ans = ' '
for i in l:
ans = ans+ ' '+ i
print(ans)
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Output:
hello geek have a geeky day
Using list comprehension to concatenate items in a list to a single string
Here, we are using list comprehension to make the items into a Python string i.e. words into sentence.
Python3
l = [ 'hello', 'geek', 'have',
'a', 'geeky', 'day']
res = " ".join([str(item) for item in l])
res
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Output:
'hello geek have a geeky day'
Using join() method to concatenate items in a list to a single string
The join() is an inbuilt string function in Python used to join elements of the sequence separated by a string separator. This function joins elements of a sequence and makes it a string.
Python3
l = ['hello', 'geek', 'have',
'a', '1', 'day']
l = ' '.join(l)
print(l)
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Output:
hello geek have a 1 day
Using map() method to concatenate items in a list to a single string
The map() function returns a map object(which is an iterator) of the results after applying the given function to each item of a given iterable. In map we passed the str as Datatype and list, this will iterate till the length of the list and join each element to form a string.
Python3
l = [ 'hello', 'geek', 'have',
'a', 'geeky', 'day']
res = " ".join(map(str, l))
print(res)
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Output:
hello geek have a geeky day
Using reduce() method to concatenate items in a list to a single string
The reduce(fun, seq) function is used to apply a particular function passed in its argument to all of the list elements mentioned in the sequence passed along. This function is defined in “functools” module.
Python3
from functools import reduce
l = ['hello', 'geek', 'have',
'a', 'geeky', 'day']
res = reduce(lambda x, y: x + ' ' + y, map(str, l))
print(res)
|
Output:
hello geek have a geeky day
The time and space complexity for all the methods are the same:
Time Complexity: O(n)
Space Complexity: O(n)
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