How to convert str to list python

Convert String to List in Python

Introduction

While programming we may need to convert a string to list in Python. That could be for any other reason. But, a question arises here, how can we convert a string to different forms of lists?

So, here in this tutorial, we are going to learn how we can convert a string into a list in Python.

Methods of converting a string to list in Python

Conversion of a string to list in Python is a pretty easy job. It can be achieved by following different methods as per our own requirements.

Here in this tutorial, we are going to deal with all the methods using which we can convert a string to list in Python for different cases. Below we have listed all the methods:

Now we are going to discuss each one of the above-mentioned techniques one-by-one.

1. String to List of Strings

When we need to convert a string to list in Python containing the constituent strings of the parent string(previously separated by some separator like ‘,’ or space), we use this method to accomplish the task.

For example, say we have a string “Python is great”, and we want a list which would contain only the given names previously separated by spaces, we can get the required list just by splitting the string into parts on the basis of the position of space.

Let us look at an example to understand it better.

Output:

In the above code:

2. String to List of Characters

What if we need a list of characters present in a string? In that case, direct type conversion from string to list in Python using the list() method does the job for us.

Certainly, if the input string is something like “abcd”, typecasting the string into a list using the list() method gives us a list having the individual characters ‘a’, ‘b’, ‘c’, ‘d’ as its elements. Take a look at the given example code below.

Output:

Understanding the code:

3. List of Strings to List of Lists

Here, we are going to see how we can combine both the above methods to convert a string to a list of character lists.

Look at the below-given example carefully,

Output:

Understand the code:

4. CSV to List

A CSV( Comma Separated Values) string, as its name suggests is a string consisting of values or data separated by commas.

Let us look at how we can convert such type of string to list in Python.

Output:

5. A string consisting of Integers to List of integers

Now we are going to convert a string consisting of only integers separated by some space, comma or etc., to a list with integer type elements.

For example, look at the code below,

Output:

Conclusion

That’s all now, this was all about converting strings into different lists using various methods. Try to use the one which suits your code and solves your purpose as well as meets up to your requirements. Questions in the comments are appreciated.

How to convert string representation of list to a list

I was wondering what the simplest way is to convert a string representation of a list like the following to a list :

Even in cases where the user puts spaces in between the commas, and spaces inside of the quotes, I need to handle that as well and convert it to:

I know I can strip spaces with strip() and split() and check for non-letter characters. But the code was getting very kludgy. Is there a quick function that I’m not aware of?

19 Answers 19

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The json module is a better solution whenever there is a stringified list of dictionaries. The json.loads(your_data) function can be used to convert it to a list.

If you have 2.6 or newer, use ast instead of eval:

Once you have that, strip the strings.

If you’re on an older version of Python, you can get very close to what you want with a simple regular expression:

This isn’t as good as the ast solution, for example it doesn’t correctly handle escaped quotes in strings. But it’s simple, doesn’t involve a dangerous eval, and might be good enough for your purpose if you’re on an older Python without ast.

There is a quick solution:

Unwanted whitespaces in the list elements may be removed in this way:

Inspired from some of the answers above that work with base python packages I compared the performance of a few (using Python 3.7.3):

Method 1: ast

Method 2: json

Method 3: no import

I was disappointed to see what I considered the method with the worst readability was the method with the best performance. there are tradeoffs to consider when going with the most readable option. for the type of workloads I use python for I usually value readability over a slightly more performant option, but as usual it depends.

If it’s only a one dimensional list, this can be done without importing anything:

** best one is the accepted answer

Though this is not a safe way, the best answer is the accepted one. wasn’t aware of the eval danger when answer was posted.

Assuming that all your inputs are lists and that the double quotes in the input actually don’t matter, this can be done with a simple regexp replace. It is a bit perl-y but works like a charm. Note also that the output is now a list of unicode strings, you didn’t specify that you needed that, but it seems to make sense given unicode input.

The junkers variable contains a compiled regexp (for speed) of all characters we don’t want, using ] as a character required some backslash trickery. The re.sub replaces all these characters with nothing, and we split the resulting string at the commas.

Python string to list – Complete tutorial

In this Python tutorial, you will learn about Python String to list. Let us see how to convert Python string to list and also we will cover the below examples:

Python string to list

Syntax:

Here is the Syntax of the split() function

Example:

Let’s take an example and check how to convert a string to a list.

In the above code first, we initialize a string ‘new_str’ and then use the split() method and pass whitespace as a delimiter which splits the words of the string, and stores them into the list.

Here is the Screenshot of the following given code

Convert a string to a list in Python

By using the Python list() function we can perform this particular task and this method takes iterable objects and converts them into the list.

Here is the code of string to list in Python

In this example, we use the concept of strip() function and it will remove spaces from the string at the first and the end of the string.

Here is the execution of the following given code

Python string to list of characters

Syntax:

Here is the Syntax of a list() method

Source Code:

In the above code, we have already taken the input string ‘Micheal’ and now we use the list() constructor and it will give us a list having the individual characters ‘M’, ‘i’ as elements.

Here is the implementation of the following given code

Check how to convert a string into a list of characters

By using the Python list comprehension method we can convert a string into a list of characters. In Python, the list comprehension method is used to build a new list. List comprehension is an easy way to define and declare lists based on existing lists.

Here is the Source code:

In the above example, a list is assigned to a variable ‘str_new’, and the list stores the items of the iterable objects. After that, we call print() statement to display the output.

Here is the execution of the following given code

Python string to list conversion

Syntax:

Here is the Syntax of the split() function

Example:

Here is the Output of the following given code

Python string to list with separator

Here is the Source Code:

Output:

Python string to list of words

Source Code:

In the above code first, we define a function ‘convert’ and then pass list ‘country_name’ as an argument. Now create a list and call print() statement to display the result.

Here is the execution of the following given code

Python string to list split

Syntax:

Here is the Syntax of the split() function

Source Code:

Here is the Output of the following given code

Python string to list of ints

Example:

In the above example we have a list ‘val_lis’ and then apply the built-in function int and get a list of integers by using the list comprehension method.

Here is the implementation of the following given code

How to convert a string list to an integer

By using the map and split() function we can solve this problem, In Python, the map() function is well efficient and easy to convert a list of strings into integer and this method always returns an iterator, convert the string into an integer list.

Source Code:

Here is the Screenshot of the following given code

Python string to list with spaces

Source Code:

Here is the Output of the following given code

How to convert a string to a list with spaces

By using the ‘*’ operator we can convert a string to a list with white spaces in Python. In this example first, we declare a list ‘new_val_lis’ and store them integer values.

Source Code:

Here is the Screenshot of the following given code

Python string to list newline

Example:

Here is the execution of the following given code

Cconvert strings into a list using newline – Another approach

By using the splitline() method we can solve this problem and this function is used to split the lines at line boundaries in Python.

Source Code:

Here is the Screenshot of the following given code

Python string to list of dictionries

Source Code:

In the above example first, we initialize a string and then use the eval() method to convert a list of dictionaries.

Here is the implementation of the following given code

Python string to list of strings

Example:

In the above code first, we consider a string, ‘pro_sting’, and then apply the split() function. It is used to break a string into a list on the given separator. In this example, we have not mentioned the separator argument is a split() function.

Here is the Output of the following given code

Python string to list by delimiter

Source Code:

In the above code first, we consider a string ‘alpha_str’ and assign them characters in single-quoted ‘ ‘. Now we can use the split() function and pass ‘,’ delimiter as an argument.

Here is the Output of the following given code

Python string to list of floats

Source Code:

In this example, we have created a string ‘flo_str’ and assign them float values. Now by using the map() function we have passed float data type as an argument and store them into a ‘new_item’ variable.

Output:

Another example by using list comprehension and eval() method

Example:

Here is the Screenshot of the following given code

By using for loop and split() method we can a string to a list of floats in Python

Source Code:

In this example, we have created a list of items by space in a string, we can use the split() and along with use for loop to iterate each item in a given list. After that use float datatype to convert each item to a float number.

Screenshot:

Python string to list array

Syntax:

Here is the Syntax of the split() method

Example:

Let’s take an example and check how to convert a string into an array

In the above example, we have split the string by using a white space delimiter.

Output:

Python string to list without split

Syntax:

Source Code:

Here is the execution of the following given code

This is how to split a string into a list without using the split() function in Python.

Python add string to list elements

Source Code:

In the above example first, we initialize a list and create a string ‘add_str’ which we have to add to a list. Appending string to a list we can use the method append() and this particular function add a string element to the last of a list without changing the list of characters.

Here is the execution of the following given code

Python string list extract substring

Syntax:

Here is the Syntax of the slice() method

Note: This method consists of three parameters start, stop, step, and the slice object is inserted within the string variable.

Example:

In the above example, we pass single integer value ‘2’ as an argument in the slice() constructor and the index value starts from 0.

Here is the execution of the following given code

Python string split to list regex

Syntax:

Here is the Syntax of re.split() function

Source Code:

In the above code first, we have created a string ‘nw_string1’ and in this string, each word is separated by underscore and comma. Now this delimiter(‘_’) is used to break the string into substrings.

Output:

Python string list remove duplicates

Let’s take an example and check how the set() method can be used to remove duplicates from the list.

Source Code:

In the above code first, we initialize a list called ‘new_str’ which contains alphabet characters. Now we declare a variable ‘rem_new_dup’ which stores the set() function and assign ‘new_str’ variable as an argument. This process deletes all duplicates from a given list.

Here is the execution of the following given code

How to remove duplicate string from list

Syntax:

Here is the Syntax of dict.keys() method

Note: This method consists of two parameters key and value.

Example:

In the above code first, we have created a string called ‘string’ which contains different countries’ names in the form of a string. Now use the dict.fromkeys() method to initialize a dictionary from the ‘string’ variable and then use the list() constructor to convert dict into a list.

Screenshot:

Python string list index

Syntax:

Here is the Syntax of a list index() method

Example:

In the above example, we have created a list ‘student_name’ which contains strings. Now I want to get the index value of ‘james’ to do this we apply the list.index() method and call the print statement to display the index value.

Here is the execution of the following given code

Python string to list of tuples

Source Code:

Here is the Output of the following given code

Python string to list of json

Source Code:

Python string to list remove spaces

Example:

Output:

Python string list to dataframe

Here is the Screenshot and code of the CSV file

Note: This code is an input string you have to use in your CSV file

Here is the implementation of the string list to the dataframe.

Source code:

In the above first we import a pandas library and then create a variable ‘df’ in which we have used the ‘read_csv’ function for importing a CSV file to dataframe format. In this method, we have assigned a ‘test.csv’ file as an argument.

Output:

Python string list max length

Source Code:

Here is the execution of the following given code

Python string list to byte array

Source Code:

Here is the implementation of the following given code

Python string vs list

Example:

Let’s take an example and check the main difference between string and list in Python

Here is the execution of the following given code

You may like the following Python tutorials:

In this Python tutorial, you will learn about Python String to list. Let us see how to convert Python string to list and also we will cover the below examples:

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How to convert a string with comma-delimited items to a list in Python?

How do you convert a string into a list?

14 Answers 14

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Trending sort is based off of the default sorting method — by highest score — but it boosts votes that have happened recently, helping to surface more up-to-date answers.

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Just to add on to the existing answers: hopefully, you’ll encounter something more like this in the future:

But what you’re dealing with right now, go with @Cameron’s answer.

The following Python code will turn your string into a list of strings:

I don’t think you need to

In python you seldom need to convert a string to a list, because strings and lists are very similar

Changing the type

If you really have a string which should be a character array, do this:

Not changing the type

Note that Strings are very much like lists in python

Strings have accessors, like lists

Strings are iterable, like lists

Strings are lists. Almost.

If you actually want arrays:

If you do not need arrays, and only want to look by index at your characters, remember a string is an iterable, just like a list except the fact that it is immutable:

All answers are good, there is another way of doing, which is list comprehension, see the solution below.

for comma separated list do the following

the strip remove spaces around words.

split() is your friend here. I will cover a few aspects of split() that are not covered by other answers.

So, if stripping of whitespaces is desired while splitting a string based on a non-whitespace delimiter, use this construct:

Python – Convert String to List

In Python, if you ever need to deal with codebases that perform various calls to other APIs, there may be situations where you may receive a string in a list-like format, but still not explicitly a list. In situations like these, you may want to convert the string into a list.

In this article, we will look at some ways of achieving the same on Python.

Converting List-type strings

A list-type string can be a string that has the opening and closing parenthesis as of a list and has comma-separated characters for the list elements. The only difference between that and a list is the opening and closing quotes, which signify that it is a string.

Let us look at how we can convert these types of strings to a list.

Method 1: Using the ast module

Python’s ast (Abstract Syntax Tree) module is a handy tool that can be used to deal with strings like this, dealing with the contents of the given string accordingly.

We can use ast.literal_eval() to evaluate the literal and convert it into a list.

Output

Method 2: Using the json module

Python’s json module also provides us with methods that can manipulate strings.

In particular, the json.loads() method is used to decode JSON-type strings and returns a list, which we can then use accordingly.

The output remains the same as before.

Method 3: Using str.replace() and str.split()

We can use Python’s in-built str.replace() method and manually iterate through the input string.

Output:

Converting Comma separated Strings

A comma-separated string is a string that has a sequence of characters, separated by a comma, and enclosed in Python’s string quotations.

To convert these types of strings to a list of elements, we have some other ways of performing the task.

Method 1: Using str.split(‘,’)

Output:

Method 2: Using eval()

However, this is NOT recommended, and should rather be avoided, due to security hazards of running potentially untrusted code.

Even so, if you still want to use this, go ahead. We warned you!

The output will be a list, since the string has been evaluated and a parenthesis has been inserted to now signify that it op is a list.

Output

This is quite long and is not recommended for parsing out comma-separated strings. Using str.split(‘,’) is the obvious choice in this case.

Conclusion

In this article, we learned some ways of converting a list into a string. We dealt with list-type strings and comma-separated strings and converted them into Python lists.