Why do we use join() function in Python?

The join() is defined as a string method which returns a string value. It is concatenated with the elements of an iterable. It provides a flexible way to concatenate the strings. See an example below.

str = “Rohan”
str2 = “ab”
# Calling function
str2 = str.join(str2)
# Displaying result
print(str2)
Output:

aRohanb

In Python, the join() function is used to concatenate a sequence of strings. It takes an iterable (such as a list or tuple) of strings as its argument and returns a single string where each element of the iterable is joined together with the string on which join() was called.

The primary reason for using join() is efficiency and readability, especially when dealing with large strings or large numbers of strings. It’s much more efficient to use join() than repeatedly concatenating strings with the + operator, especially as the number of strings grows. This is because join() utilizes optimized string concatenation methods implemented in Python, resulting in faster execution.

For example:

python
my_list = ["Hello", "World", "!"]
joined_string = " ".join(my_list)
print(joined_string)

Output:

Hello World !

Here, join() efficiently joins the strings in the my_list with a space character in between each element, resulting in the string “Hello World !”.