scott.greenough
Python Initialize List: How To Guide and Instructions with 3 Methods
Introduction
In Python, a list is a data structure that stores a collection of items. The items can be of any data type, such as integers, strings, or other lists. You can create a list by using the list() constructor or by using square brackets ([]) to enclose a comma-separated list of items.
In order to initialize a list in Python, there are three methods you can use:
1. Using the list() constructor
The list() constructor is the simplest way to create a list in Python. It takes an arbitrary number of arguments, which are all converted to strings and then joined together into a single string.
For example, the following code creates a list containing the numbers 1, 2, and 3:
list(1,2,3)
You can also create lists with more than one dimension by using multiple pairs of brackets. For example, the following code creates a two-dimensional list with four items:
list([[1,’apple’], [2,’banana’]], [[3,’orange’], [4,’pear’]])
Give your kids a head start! Learn Python using an intuitive and user-friendly approach with CodeMonkey. Sign up now!
2. Using square brackets ([])
You can also create lists using square brackets, which is the most common way to create lists in Python. The items in the list do not have to be of the same data type.
For example, the following code creates a list containing the numbers 1, 2, and 3:
list = []
list.append(1)
list.append(2)
list.append(3)
print(list)
You can also use negative indices with the square bracket notation. Negative indices start from the end of the list and are used to access elements in reverse order. For example, the following code prints out the last element in the list:
print(list(-1))
3. Using the list comprehension syntax
List comprehensions are a concise way to create lists in Python. They are often used to create lists that result from some kind of transformation or filtering operation on another list.
For example, the following code creates a list of all the numbers between 1 and 10 that are divisible by 3:
list = []
for x in range(1, 11):
if (x % 3 == 0):
list.append(x)
print(list)
This method is generally considered more efficient than the list() constructor or the append() method since it doesn’t require creating and storing intermediate list objects.
Some of the basic operations you can perform on lists include:
– Indexing: You can access individual elements in a list by using their index. For example, the following code prints out the first and last elements in a list:
list = [‘a’, ‘b’, ‘c’]
print(list(0))
print(list(-1))
– Slicing: You can also extract sublists from a list by using slicing notation. Slicing notation consists of two indices separated by a colon (:). The first index specifies the starting point of the slice, and the second index specifies the endpoint (exclusive). For example, the following code prints out the middle element of a list:
list = [‘a’, ‘b’, ‘c’, ‘d’]
print(list(1:3))
– Finding elements: You can use the in operator to check if an element is in a list. For example, the following code prints out whether or not ‘b’ is in the list:
list = [‘a’, ‘b’, ‘c’]
if (‘be in list):
print(‘b is in the list)
else:
print(‘b is not in the list)
– Sorting: You can sort a list using the sort() method. For example, the following code sorts a list in ascending order:
list = [‘c’, ‘a’, ‘b’]
list.sort()
print(list)
You can also sort a list in descending order bypassing the reverse=True argument to the sort() method.
– Looping: You can loop through the elements in a list using a for loop. For example, the following code prints out all the elements in a list:
list = [‘a’, ‘b’, ‘c’]
for element in list:
print(element)
You can also use the enumerate() function to loop through a list and get both the index and the value of each element. For example, the following code prints out the index and value of each element in a list:
list = [‘a’, ‘b’, ‘c’]
for index, element in enumerate(list):
print(index, element)
Python also has a number of built-in functions that can be used on lists. Some of the most common ones are listed below:
– len(): Returns the length of a list (the number of elements in a list).
– max(): Returns the maximum value in a list.
– min(): Returns the minimum value in a list.
– sum(): Returns the sum of all the values in a list.
– sorted(): Returns a sorted copy of a list.
– reversed(): Returns a reversed copy of a list.
Basic rules when initializing variables:
1. Start with lowercase
When you initialize a variable, you always want to start with lowercase. This makes it easier to read and understand your code, and it also helps to avoid potential naming conflicts.
2. Use underscores to separate words
If you need to use more than one word to describe your variable, then you can use underscores to separate those words. For example, if you want to initialize a variable that represents the number of days in a week, you could use the name num_days_in_week.
3. Be descriptive
Your variable names should be descriptive enough that someone else reading your code can understand what they represent without having to look up the meaning of the variables in your code comments.
4. Avoid using Python keywords
Python has a list of keywords that have special meaning in the language, and you should avoid using those keywords as variable names. For example, if you try to use the name list as a variable name, you will get an error because list is a Python keyword.
5. Use meaningful variable names
Your variable names should be chosen so that they are meaningful and easy to remember. For example, if you are working with a list of numbers, using a variable name like nums or numbers would make sense. But if you choose a variable name like x or y, it will be more difficult to understand what your code is doing.
Conclusion
In this article, you’ve learned about how to initialize lists in Python. You’ve also learned about some of the rules that you should follow when choosing variable names. By following these guidelines, you can make your code more readable and easier to understand.
How To Rename A File In Python and Change File Extension
Python is one of the most common and powerful programming languages. Experts reveal that its versatile and straightforward nature makes it an easy and preferable option among most individuals. You can use this tool for your various tasks, making it popular in programming. Regardless of your experience level, you can improve your productivity using a few Python code lines.
Many individuals find it ideal to use the language in performing various functions and solving problems. Renaming and moving files is common when using Python to achieve different tasks. Nevertheless, many individuals find it challenging to rename their files and change the extensions. This article explores how to rename a file in python and change file extension.
Get the File Path of the Specific File
Despite the variations of renaming folders with Python, the first or primary step is getting the right file path of your preferred program. Experts recommend that you need to understand the location of the specific folder. Check your system to identify the folder with the program you need to change the name. The program should be able to tell the complete path of the specific program we need to rename in the Python scripts or directories. Let’s see how you can find the path in Linux and windows:
Windows
You can get the file path when using windows by opening Explorer. Then proceed to the place or location with the file and click the path. Ensure that you choose the one you intend to change the name of.
Give your kids a head start! Learn Python using an intuitive and user-friendly approach with CodeMonkey. Sign up now!
Linux
Understanding the path in Linux will be vital before renaming your files using Python. We’ve got various ways or methods you can use to find the right path in Linux. For instance, you can start by opening the Terminal Window and using the Xclip or readlink command-line application.
Copying the Specific Path of the File
After getting the right path, you can proceed to copy it to make it easy for you to transfer to another location when changing the name. You can copy the path by right-clicking it after marking or highlighting it. Ensure that you copy the entire name or code to get a successful renaming process.
Import the Operating System Module
You can proceed to import a specific python module, s,’ after highlighting or copying the path. Remember, importing the module is easy, involving getting the specific module from your location. The different operating systems have different importation processes you must consider for successful results.
Renaming the File
After importing the file, you’ll be ready to rename it using the module. If the folder has a long path, you can begin by creating a string of variables. Below is a process for changing the name of your file with Python:
Changing the file name in windows
Add an extra / to all the subfolders to change the name on your windows operating system. The process also involves adding the path in all the files you want to rename and the results. You can add a string variable to the path using the .’ It’ll be vital to perform the process to prevent the file from moving to the Python Script folder. Besides preventing the program from moving, the process will also rename the folder.
Renaming the file in Linux
The different paths make it slightly different from renaming in Linux. Nevertheless, you can use the same process in windows but consider the different paths when renaming Linux.
Renaming Multiple Files in Python
Besides renaming a single program, there is an increased need to understand the procedure of renaming many programs in the pythons. Let’s look at how you can rename numerous files in Python:
Experts reveal that there are various methods you can use to rename multiple files. The common method is to generate the Python list using the folder names you intend to change. Nevertheless, it may not be an ideal opinion when you have to change the name of various files. Preferably, you can use other alternatives, like the istdir’ or nmatch.’ Ensure you choose a method that provides an optimal result or achieves it through a simple process.
When renaming multiple programs, the first step is creating a list of text files. These text files should be present in the particular folder; for example, you can consider any_Files’ as your preferred subfolder. Remember to add the subfolder on the file_path string.
You can proceed to get through the loop to each program and rename them. Experts recommend that you use a file-path string from a specific code chunk with the location. Changing the path to the folder will also be appropriate if you want to rename it to a different folder.
When creating the folder, you can use an enumerate method to provide a unique name. Experts prefer that you use the str method or process in changing the data type. When using Linux, you have to get a different path to find the specific one you need to rename. You can also consider other appropriate and straightforward functions, like abs(), to get more value in the process.
How to rename different files by replacing the file name’s character
Besides the straightforward process of renaming your multiple files, you may require to replace certain characters in different folders. For instance, the process may require you to replace underscores in the name. With the process, you’ll have to replace both the symbols and the files.
Experts reveal that the process involves identifying the location before starting the process. You can then proceed to rename the files and the varying characters. Despite the similarity, you have to change the file_path string when renaming the specific files using the Linux process.
Bottom Line
Renaming files and changing extensions is common when having programming tasks like Python. Despite the straightforward process of renaming these files, some individuals find it difficult to rename different files using Python. The process involves identifying the location, copying the file’s specific path, importing the OS module, and renaming the folder. You can read the above guide to understand how to rename the files in Linux and windows.
How To Break Line In Python: Full Explanation
Because Python supports indirect line continuation, it gives you the freedom to break lines of code that are too long. Also, you can limit all the lines of codes up to 79 characters. Besides, you can use Python’s new line character to mark the end of a specific line as well as the beginning of a line. In this post, you can learn how to break long lines and add another new line in Python.
WHAT IS PYTHON’S NEW LINE?
Typically, one of the common practices in coding involves breaking long lines and displaying the content in a newly formed line. As a result, it improves readability to a great extent of the output content.
In addition, you can come across the newly formed line character several times when working with files. Therefore, it is important to understand how you can add a new line by familiarizing yourself with everything that makes the new character line works.
BREAKING LINES OF CODE IN PYTHON:
No doubt, when you break a long line of code, it increases the overall lines of code as well. Apart from that, it improves the readability of the code. However, you should keep in mind that the new line of code shouldn’t exceed more than 79 characters.
As said earlier, Python supports indirect line continuation. It means that all the expressions that you find inside the curly braces, square brackets, or even parenthesis could be broken into simple and multiple lines of code. Here is a great example that would help you to understand better.
Give your kids a head start! Learn Python using an intuitive and user-friendly approach with CodeMonkey. Sign up now!
The long print() function is broken into several lines in different ways.
print(“Allen”, “Bob”, “Christine”, “David”, “Edmund”, “Fernando”, “Gabriel”, “Hobart”, “Isaac”)
print(
“Allen”, “Bob”, “Christine”, “David”, “Edmund”, “Fernando”, “Gabriel”, “Hobart”, “Isaac”
)
print(
“Allen”,
“Bob”,
“Christine”,
“David”,
“Edmund”,
“Fernando”,
“Gabriel”,
“Hobart”,
“Isaac”
)
Hence, there are several ways through which you can break lengthy lines of code in Python. Also, you can check out the different official styles on their website that make you understand the best practices that you can think of. However, before you proceed further, don’t forget that there is a unique way that helps you automatize the whole line-breaking procedure.
AUTO BREAKING OF THE LINES OF CODE IN PYTHON
There is no denying that some of the popular code editors that you use in Python allow you to install plugins because of the code style guidelines with ease. The best part about these plugins is that they help you auto-format the long lines of code.
In short, the plugin is responsible to automate the format code without difficulties. It means that the plugin makes sure that no single line exceeds the predetermined limit of 79 characters. In VSCode, for example, you can automatically format a long code when saving the same. Next, let’s discuss some examples where you can split the certain expression into several lines.
BREAKING A STRING TO MULTIPLE LINES OF CODE IN PYTHON:
When it comes to breaking a string into multiple lines, the best way is to wrap every string into a new line between the double quotation marks. Here is an example to clear your doubts.
print(
“It is going to be”
“a long string that”
“it might be a good idea”
“to consider breaking the line”
“without extending it to the right”
)
However, you can’t do the following.
print(
“It is going to be
a long string that
it might be a good idea
to consider breaking the line
without extending it to the right”
)
BREAKING FUNCTION ARGUMENTS TO MULTIPLE LINES:
When your function involves lots of arguments and it results in extending the line of code to the right, you can break the expression into several lines of code in Python. Here is an example.
def example_function(second_number, fourth_number, sixth_number, eighth_number):
pass
So, despite doing the above one, you can do the following instead.
def example_function(
second_number,
fourth_number,
sixth_number,
eighth_number
):
pass
BREAKING A LIST INTO MULTIPLE LINES:
To give you a better understanding, let’s begin by creating a 3×3 matrix using a list.
For example: matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
Although it might look fine, you should write a matrix in a table format. As such, it would make it look similar to a table comprising values. Now, if you want to convert the same in Python, you have to break the matrix into several lines. Here is how to do it the right way.
matrix = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
]
BREAKING DICTIONARIES INTO MULTIPLE LINES:
You can do the same with a dictionary just like you did when breaking the list declaration into multiple lines. Let’s understand the thing with an example.
student = {“name”: “Allen”, “age”: 23, “married”: False, “graduated”: False, “hobbies”: [“Gym”, “Jogging”, “Boxing”]}
Instead of writing a long-expression like the above one. You can break the dictionary into several lines so that it becomes easy to understand. Here it is.
student = {
“name”: “Allen”,
“age”: 23,
“married”: False,
“graduated”: False,
“hobbies”: [“Gym”, “Jogging”, “Boxing”]
}
BREAKING A MATHEMATICAL OPERATION INTO MULTIPLE LINES:
When it is about breaking a chain of binary operations, you should split the line just before the operator. That way, it will make the code readable because the binary operators aren’t scattered all over the place. Take a look at this example to clear your doubts.
income = gross_wage + tax_interest + (dividend – qualified_dividend) – ira_deductions – student_loans_interests
Instead of doing the above, you can do the following.
income = (gross_wage
+ tax_interest
+ (dividend – qualified_dividend)
– ira_deductions
– student_loans_interest)
BREAKING THE COMPARISONS TO MULTIPLE LINES:
Just like with other expressions, certain comparisons take up a considerable amount of space. Therefore, you can break the line if you don’t want those long lines of comparison. Here is an example.
if (is_raining == True and
is_warm == True and
is_bright == True and
is_dark == True):
print(“How is this possible…?)
CONCLUSION
So, it is clear that the implicit line continuation in Python allows it to break long lines into multiple line expressions. Also, it gives good readability. Hence, you can put line breaks whenever you want.
Thank You For Subscribing
Thank you for subscribing… in just a few minutes you will get an email from me with your free “Coding Startup Guide”.
The email will be from info@pythoncoders.org – that’s me 🙂
You can even whitelist this email to be sure you get all my messages with cool tips, videos, and downloads so that you can receive information, tips, access to tutorials and offers to help you with your learning and advancement. I look forward to providing killer info for you over the next few weeks. (learn how to whitelist an email here)
While You Are Waiting… Check Out These Killer Learning Resources…
-
Black Friday & Cyber Monday Flash Sale! Up to 65% off yearly subscriptions. Valid 11/17-12/8.
-
I love coding! is a good site for either Full Stack development or a focus on the Front End. All this for a lifetime membership of only $99!
-
Get your kids coding at Code Monkey. A great site that makes it fun and easy to learn the Python programming language. A great resource for kids!
Thank You And I Hope You Enjoy The “Coding Startup Guide”
Scott @ PythonCoders
Hello world!
Welcome to WordPress. This is your first post. Edit or delete it, then start writing!