Split and join a string in Python
Last Updated : 01 May, 2025
The goal here is to split a string into smaller parts based on a delimiter and then join those parts back together with a different delimiter. For example, given the string "Hello, how are you?", you might want to split it by spaces to get a list of individual words and then join them back together with a different delimiter like a hyphen (-) to create a formatted string. The result would be "Hello,-how-are-you?".
Using split() and join()
split() function divides the string into a list of words and join() reassembles them with a specified separator. It is highly efficient and commonly used in Python for basic string manipulations.
Python a = "Hello, how are you?" b = a.split() # Split by space c = "-".join(b) # Join with hyphen print(b) print(c)
Output['Hello,', 'how', 'are', 'you?'] Hello,-how-are-you?
Explanation:
- split() divides the string into a list of words, split by spaces by default.
- "-".join(b) reassembles the list into a string with hyphens between the words.
Using re.split() and '-'.join()
In cases needing advanced splitting e.g., handling multiple spaces or different delimiters, re.split() from the re module offers more flexibility. However, it’s less efficient than split() for simple cases due to the overhead of regular expression processing.
Python import re a = "Hello, how are you?" b = re.split(r'\s+', a) # Split by spaces c = "-".join(b) # Join with a hyphen print(b) print(c)
Output['Hello,', 'how', 'are', 'you?'] Hello,-how-are-you?
Explanation:
- re.split(r'\s+', a) split the string by one or more spaces, providing more flexibility for advanced splitting.
- "-".join(b) joins the list of words with hyphens.
Using str.partition() and str.replace()
This method splits the string manually using partition(), iterating over it to separate head and tail parts. After splitting, replace() or manual manipulation joins the parts. While functional, it’s less efficient due to multiple iterations and extra logic.
Python a = "Hello, how are you?" words, rem = [], a # Split by space manually while rem: head, _, rem = rem.partition(" ") if head: words.append(head) c = "-".join(words) # Join with hyphen print(words) print(c) Output['Hello,', 'how', 'are', 'you?'] Hello,-how-are-you?
Explanation:
- partition(" ") splits the string into three parts, before the first space (head), the space itself (sep) and after the space (tail). This process repeats until the string is fully split.
- Loop ensures all words are extracted and added to the list words.
Using str.split() with list comprehension
This method splits the string with split() and uses a list comprehension to process or filter the list. While more compact and readable, it adds an extra step, reducing efficiency compared to using split() and join() directly.
Python a = "Hello, how are you?" # Split by space b = [word for word in a.split()] # Join with a hyphen c = "-".join(b) print(b) print(c)
Output['Hello,', 'how', 'are', 'you?'] Hello,-how-are-you?
Explanation:
- [word for word in a.split()] splits a by spaces into a list of words .
- "-".join(b) joins the words in b with hyphens.
Related Articles
Similar Reads
Split a String by a Delimiter in Python In Python Programming, the split() method is used to split a string into a list of substrings which is based on the specified delimiter. This method takes the delimiter as an argument and returns the list of substrings. Along with this method, we can use various approaches wot split a string by the
2 min read
Python | Exceptional Split in String Sometimes, while working with Strings, we may need to perform the split operation. The straightforward split is easy. But sometimes, we may have a problem in which we need to perform split on certain characters but have exceptions. This discusses split on comma, with the exception that comma should
4 min read
Python - Split String on all punctuations Given a String, Split the String on all the punctuations. Input : test_str = 'geeksforgeeks! is-best' Output : ['geeksforgeeks', '!', 'is', '-', 'best'] Explanation : Splits on '!' and '-'. Input : test_str = 'geek-sfo, rgeeks! is-best' Output : ['geek', '-', 'sfo', ', ', 'rgeeks', '!', 'is', '-', '
3 min read
Python - Splitting Text and Number in string Given a string containing both letters and numbers, the task is to separate the text (letters) and the numbers into two separate outputs. For example, if the input is "abc123", the output should be "abc" and "123". Let's discuss various ways in which we can achieve this in Python.Using for loopThis
3 min read
Python | Split flatten String List Sometimes, while working with Python Strings, we can have problem in which we need to perform the split of strings on a particular deliminator. In this, we might need to flatten this to a single String List. Let's discuss certain ways in which this task can be performed. Method #1 : Using list compr
7 min read