Updated December 8, 2023
What is String in Python?
A string in Python is a group of characters. Strings can be enclosed in double quotes (“”) and single quotes (”). In Python, a string is the built-in data type used most. Strings are immutable in Python, meaning you can change strings’ characters once declared.
Various operations can be performed on strings, like slicing, concatenation, and formatting. You can also perform multiple operations with built-in functions and modules like len(), str(), and re.
An example of string is,
myString = "Welcome to EDUCBA"
Table of content
- What is String in Python?
- What is a List in Python?
- Why convert string to list in Python?
- Conversion of String into List in Python
- Best practices and tips
- Common pitfalls and how to avoid them
What is a List in Python?
List in Python is a data structure. Square brackets [] are used to define lists in Python. Each value of the list is known as an element. Lists are mutable in Python. It means you can also change and modify any list value after declaration. Python lists can also be ordered.
You can store the collection of data using a list. An example of a list in Python is,
myCourse = [1, 2, 3, "Java," "Python," "C++"]Why convert string to list in Python?
Conversion of a string into a list in Python is helpful in many scenarios. After converting a string into a list, you can manipulate and process each character. These are the following reasons why the conversion of a string into a list is essential:
- The list provides direct access to any element in Python so that you can manipulate any of them.
- Python Strings are immutable, meaning you can not modify any character after creating it. However, lists are mutable; you can change any element even after making it.
- Lists in Python provide more operations on it over Strings.
- If your Python code has various functions that use lists, then converting a string into a list is very useful.
Conversion of String into List in Python
You must remove spaces and other special characters to convert a string into a list. You can use split() to do this. This split string into substrings based on delimiter and returns a list of these substrings.
For example,
mySentence = "This is sample sentence"
myWords = mySentence.split()
print(myWords)Output:
It is a list of substrings of the above-given strings.
Now, we will discuss the ten most used methods to convert strings into lists in Python.
1. Using list() method
In Python, list() is a built-in datatype used to store items. You can use it to convert one datatype into a list.
Example:
phrase = "Coding is fun"
characters = list(phrase)
print(characters)Output:
2. Using List Comprehension
In this method, you can iterate over the string and convert it to a list of characters.
Example:
phrase = "Coding is fun"
character_list = [char for char in phrase]
print(character_list)Output:
3. Using split() method
In Python, a split is a built-in function. It provides string-to-list conversion by using delimiters to separate strings. If no delimiter is specified, then the algorithm does it. You can split strings and convert them into a list of characters by using the split() method. So, you can convert a string into a list using this method. Then, you can convert each word into a list of characters. You can remove whitespaces by using delimiters. This method is proper when converting a sentence into a list of phrases.
Example:
phrase = "Coding is fun"
word_list = phrase.split()
print(word_list)It will give a list of words,
Consider this example to convert a string into a list of characters using the split() method,
Example:
phrase = "Coding is fun"
character_list = [char for word in phrase.split() for char in word]
print(character_list)It will give a list of symbols, unlike the above example,
4. Using string slicing
You can use slicing to convert a string into a list. It iterates data according to our needs. Colon(:) is used to cut anything in Python.
Example:
def Convert(string):
list1 = []
list1[:0] = string
return list1
# Driver code
phrase = "Coding is fun"
print(Convert(phrase))Output:
5. Using re.findall() method
You can use regular expression and pattern matching to convert a string into a list. You can compare all alphabets according to pattern and return a list of characters. This method is robust.
Example:
import re
# Uses re.findall method
def Convert(string):
return re.findall('[a-zA-Z]', string)
# Driver code
phrase = "Coding is fun"
print(Convert(phrase))Output:
6. Using enumerate function
You can use the enumerate in-built function to convert string to list. This function is used when dealing with iterators. It adds count, and it is an enumerating object. Then, it can be used for loops and lists.
Example:
phrase = "Coding is fun"
characters = [char for a char in enumerate(phrase)]
print(characters)Output:
7. Using JSON
In Python, a JSON module can be used to load data.
Example:
import json
phrase = "Coding is fun"
characters = list(phrase)
stringA = json.dumps(characters)
# Type check
res = json.loads(stringA)
# Result
print(res)Output:
8. Using ast.literal
There is ast(Abstract Syntax Trees) module in Python. This ast module has literal_eval, which can convert strings to lists.
Example:
import ast
phrase = "Coding is fun"
characters = list(phrase)
# Converting a list to the string representation
ini_list = str(characters)
# Converting string to the list using ast.literal_eval
res = ast.literal_eval(ini_list)
# Printing final result and its type
print(res)Output:
9. Using splitlines() method
You can use the splitlines() method in Python for this conversion. We can split a string into a list based on new line characters (\n). This method is used to separate text into lines.
Example:
phrase = "Coding\nis\nfun"
lines = phrase.splitlines()
print(lines)Output:
10. Using partition method
The partition() method can split the string into parts. These parts are based on separators. It returns tuples of these parts, including the separator. This method can split the string into three parts, including a separator.
Example:
myString = "Coding:is:fun"
myList = myString.partition(':')
print(myList)Note that the partition() method returns only a tuple of three parts, including the separator. So, the output will be,
Since this is a tuple, it is also immutable like strings.
Best Practices and Tips
These are best practices and tips while choosing and working with these methods.
- It would be best to consider factors like readability, performance, and nature of your data while choosing any of these methods.
- You should handle the required whitespaces and special characters in a given string. Otherwise, you may get the error.
- When you work with external data, you must implement error-handling mechanisms.
- The code should be easy to understand. Use meaningful variable names, comments, and docs strings to explain the purposes and functionality of your code.
- Consider the compatibility of data types after converting a string into a list.
Common Pitfalls and how to avoid them
These are some pitfalls and how you should avoid them:
- Since strings are immutable and lists are mutable. So, always lists for later modification purposes.
- You should avoid eval() for security and use ast.literal_eval() for safer conversions.
- When you use re.findall(), you should care about cases where regular expressions do not match any characters in the string. You need to check for empty lists and handle them.
- When working with enumerate(), you should care about it as it returns tuples that contain index and character. If you only need the characters, then use list comprehension without enumeration.
- You should know delimiters using methods like split() and splitlines(). If incorrectly used and handled, it may result in unexpected list elements.
Conclusion
Strings and Lists are data types in Python. Strings are immutable, and lists are mutable in Python. Using various built-in Python functions, you can convert a string into a list and vice-versa. We have discussed different methods to convert strings to lists. split() method is the most used method available for any object string in Python. You can convert a string into substrings based on a delimiter using the split() method.
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