Author name: Shikha Mishra

Python Dictionary:

Dictionaries are Python’s implementation of a data structure that is more generally known as an associative array. A dictionary consists of a collection of key-value pairs. Each key-value pair maps the key to its associated value.Keys are unique within a dictionary while values may not be.

Creating a dictionary:

Each key is separated from its value by a colon (:), the items are separated by commas, and the whole thing is enclosed in curly braces. An empty dictionary without any items is written with just two curly braces, like this: {}.

The values of a dictionary can be of any type, but the keys must be of an immutable data type such as strings, numbers, or tuples.Dictionary keys are case sensitive, same name but different cases of Key will be treated distinctly.

Output:

If we attempt to access a data item with a key, which is not part of the dictionary, we get an error as follows −

Dictionary can also be created by the built-in function dict(). An empty dictionary can be created by just placing to curly braces{}.

Output:

Nested Dictionary:

Adding elements to a Dictionary:

In Python Dictionary, Addition of elements can be done in multiple ways. One value at a time can be added to a Dictionary by defining value along with the key e.g. Dict[Key] = ‘Value’. Updating an existing value in a Dictionary can be done by using the built-in update() method. Nested key values can also be added to an existing Dictionary.While adding a value, if the key value already exists, the value gets updated otherwise a new Key with the value is added to the Dictionary.

Output:

Accessing elements from a Dictionary:

In order to access the items of a dictionary refer to its key name.Key can be used inside square brackets.

Accessing element of a nested dictionary:

In order to access the value of any key in nested dictionary, use indexing []

Delete Dictionary Elements:

ou can either remove individual dictionary elements or clear the entire contents of a dictionary. You can also delete entire dictionary in a single operation.

To explicitly remove an entire dictionary, just use the del statement. Following is a simple example −

Properties of Dictionary Keys:

Dictionary values have no restrictions. They can be any arbitrary Python object, either standard objects or user-defined objects. However, same is not true for the keys.

There are two important points to remember about dictionary keys −

(a) More than one entry per key not allowed. Which means no duplicate key is allowed. When duplicate keys encountered during assignment, the last assignment wins.

(b)Keys must be immutable. Which means you can use strings, numbers or tuples as dictionary keys but something like [‘key’] is not allowed.

Conclusion:

In this tutorial, you covered the basic properties of the Python dictionary and learned how to access and manipulate dictionary data.

Convert Python String to Int:

To convert a string to integer in Python, use the int() function. This function takes two parameters: the initial string and the optional base to represent the data. In Python an strings can be converted into a integer using the built-in int() function. The int() function takes in any python data type and converts it into a integer.But use of the int() function is not the only way to do so. This type of conversion can also be done using thefloat() keyword, as a float value can be used to compute with integers.

Below is the list of possible ways to convert an integer to string in python:

1. Using int() function:

Syntax: int(string)

Example:

Output:

As a side note, to convert to float, we can use float() in python:

Example:

Output:

2. Using float() function:

We first convert to float, then convert float to integer. Obviously the above method is better (directly convert to integer).

Syntax: float(string)

Example:

Output:

If you have a decimal integer represented as a string and you want to convert the Python string to an int, then you just follow the above method (pass the string to int()), which returns a decimal integer.But By default, int() assumes that the string argument represents a decimal integer. If, however, you pass a hexadecimal string to int(), then you’ll see a ValueError

The error message says that the string is not a valid decimal integer.

When you pass a string to int(), you can specify the number system that you’re using to represent the integer. The way to specify the number system is to use base:

Now, int() understands you are passing a hexadecimal string and expecting a decimal integer.

Conclusion:

This article is all about how to convert python string to int.All methods are clearly explained here. Now I hope you’re comfortable with the ins and outs of converting a Python string to an int.

Python is not just one of the leading programming languages, but also a top choice for dealing with big data and data science projects. The fact that it is among the easiest languages to learn makes the high-level, interpreted, general-purpose programming language even more lucrative.

For using Python on a system, the user first needs to install the Python environment. It will also install the Python interpreter, which is responsible for carrying out Python code execution. It is possible to run Python code directly from the terminal using the Python interpreter.

Python is a well known high-level programming language. The Python script is basically a file containing code written in Python. The file containing python script has the extension ‘.py’ or can also have the extension ‘.pyw’ if it is being run on a windows machine. To run a python script, we need a python interpreter that needs to be downloaded and installed.

Scripts vs Modules:

A Python script is a collection of commands in a file designed to be executed like a program. The file can of course contain functions and import various modules, but the idea is that it will be run or executed from the command line or from within a Python interactive shell to perform a specific task. Often a script first contains a set of function definitions and then has the main program that might call the functions.

Scripts are always processed by some kind of interpreter, which is responsible for executing each command sequentially.

A plain text file containing Python code that is intended to be directly executed by the user is usually called script, which is an informal term that means top-level program file.

On the other hand, a plain text file, which contains Python code that is designed to be imported and used from another Python file, is called module.

So, the main difference between a module and a script is that modules are meant to be imported, while scripts are made to be directly executed.

Different ways to run Python Script:

1. Interactive Mode
2. Command Line
3. Text Editor
4. IDE (PyCharm)

1.Interactive Mode:

Interactive mode, also known as the REPL provides us with a quick way of running blocks or a single line of Python code. The code executes via the Python shell, which comes with Python installation. Interactive mode is handy when you just want to execute basic Python commands or you are new to Python programming and just want to get your hands dirty with this beautiful language.

To access the Python shell, open the terminal of your operating system and then type “python”. Press the enter key and the Python shell will appear. This is the same Python executable you use to execute scripts, which comes installed by default on Mac and Unix-based operating systems.

The >>> indicates that the Python shell is ready to execute and send your commands to the Python interpreter. The result is immediately displayed on the Python shell as soon as the Python interpreter interprets the command.

To run your Python statements, just type them and hit the enter key. You will get the results immediately, unlike in script mode. For example, to print the text “Hello World”, we can type the following:

2.Command Line:

To run a Python script store in a ‘.py’ file in command line, we have to write ‘python’ keyword before the file name in the command prompt.

python hello.py

You can write your own file name in place of ‘hello.py’.

3.Text Editor :

Python’s standard distribution includes IDLE as the default IDE, and you can use it to write, debug, modify, and run your modules and scripts.

Other IDEs such as Eclipse-PyDev, PyCharm, Eric, and NetBeans also allow you to run Python scripts from inside the environment.

Advanced text editors like Sublime Text andVisual Studio Code also allow you to run your scripts.

4.IDE (PyCharm):

To run Python script on a IDE like PyCharm you will have to do the following:

• Create a new project.
• Give a name to that project as ‘NewProject’ and click on Create.
• Select the root directory with the project name we specified in the last step. Right click on it, go in New and click on ‘Python file’ option. Then give the name of the file as ‘hello’ (you can specify any name as per your project requirement). This will create a ‘hello.py’ file in the project root directory.
  Note: You don’t have to specify the extension as it will take it automatically.

Now write the below Python script to print the message:

print('Hello World !')

Conclusion:

With the reading of this tutorial, you have acquired the knowledge and skills you need to be able to run Python scripts and code in several ways and in a variety of situations and development environments.

Python code editors are designed for the developers to code and debug program easily. Using these Python IDEs(Integrated Development Environment), you can manage a large codebase and achieve quick deployment.

Developers can use these editors to create desktop or web application. The Python IDEs can also be used by DevOps engineers for continuous Integration.

What are IDEs and Code Editors?

Whether you are new to this game or you are a veteran player, you need an IDE (Integrated Development Environment) or a code editor to showcase your coding skills and talent. An IDE is a software that consists of common developer tools into a single user-friendly GUI (Graphical User interface). An IDE majorly consists of a source code editor for writing software code, local build automation for creating a local build of the software like compiling computer source code. Lastly, it has a debugger, a program for testing other programs. An IDE can have many more features apart from these & those vary for each IDE.

Code editors are also software; it is like a text editor with some added functionalities. It is not an IDE as an IDE has many developer tools. Depending upon the language one codes on the editor, it highlights special keywords and gives some suggestions. Sublime Text, Atom, Visual Studio Code are some of the popular code editors.

Requirements for a Good Python Coding Environment:

We have listed some major and standard features and requirements required by every project in its build phase and after. A project can have more requirements than mentioned below, but these are the basic ones, and IDE must possess.

• Save and Reload Source Code

An IDE or editor must save your work and reopen everything later, in the same state it was in when you left, thus saving time for development.

• Execution from Within the Environment

It should have a built-in compiler to execute your code. If you are not executing it in the same software, then probably it is a text editor.

• Debugging Support

The debugger in most IDEs provides stepping through your code and applying breakpoints for the code’s partial execution.

• Syntax Highlighting

Being able to spot keywords, variables quickly, and symbols in your code make reading and understanding code much easier.

• Automatic Code Formatting

This is an interesting feature; the code indents itself as the developer uses loops, functions, or any other block code.

Top Python IDEs and Code Editors:

1.Pycharm:

PyCharm is an IDE for professional developers. It is created by JetBrains, a company known for creating great software development tools.

There are two versions of PyCharm:

• Community – free open-source version, lightweight, good for Python and scientific development
• Professional – paid version, full-featured IDE with support for Web development as well

PyCharm provides all major features that a good IDE should provide: code completion, code inspections, error-highlighting and fixes, debugging, version control system and code refactoring. All these features come out of the box.

Personally speaking, PyCharm is my favorite IDE for Python development.

The only major complaint I have heard about PyCharm is that it’s resource-intensive. If you have a computer with a small amount of RAM (usually less than 4 GB), your computer may lag.

2.IDLE:

When you install Python, IDLE is also installed by default. This makes it easy to get started in Python. Its major features include the Python shell window(interactive interpreter), auto-completion, syntax highlighting, smart indentation, and a basic integrated debugger.

IDLE is a decent IDE for learning as it’s lightweight and simple to use. However, it’s not for optimum for larger projects.

3.Sublime Text 3:

Sublime Text is a popular code editor that supports many languages including Python. It’s fast, highly customizable and has a huge community.

It has basic built-in support for Python when you install it. However, you can install packages such as debugging, auto-completion, code linting, etc. There are also various packages for scientific development, Django, Flask and so on. Basically, you can customize Sublime text to create a full-fledged Python development environment as per your need.

You can download and use evaluate Sublime text for an indefinite period of time. However, you will occasionally get a pop-up stating “you need to purchase a license for continued use”.

4.Atom:

Atom is an open-source code editor developed by Github that can be used for Python development (similar Sublime text).

Its features are also similar to Sublime Text. Atom is highly customizable. You can install packages as per your need. Some of the commonly used packages in Atom for Python development are autocomplete-python, linter-flake8, python-debugger, etc.

Personally speaking, I prefer Atom to Sublime Text for Python development.

5.Visual Studio Code:

Visual Studio Code (VS Code) is a free and open-source IDE created by Microsoft that can be used for Python development.

You can add extensions to create a Python development environment as per your need in VS code. It provides features such as intelligent code completion, linting for potential errors, debugging, unit testing and so on.

VS Code is lightweight and packed with powerful features. This is the reason why it becoming popular among Python developers.

6.Spyder:

Spyder is an open-source IDE usually used for scientific development.

The easiest way to get up and running up with Spyder is by installing Anaconda distribution. If you don’t know, Anaconda is a popular distribution for data science and machine learning. The Anaconda distribution includes hundreds of packages including NumPy, Pandas, scikit-learn, matplotlib and so on.

Spyder has some great features such as autocompletion, debugging and iPython shell. However, it lacks in features compared to PyCharm.

7.Thonny:

Thonny is an integrated development environment (IDE). Developed by the University of Tartu in Estonia, this software has been designed mainly to make life easier for beginners in Python by providing them with a simple, lightweight IDE. Still, with excellent features, it is a bit like the beginner’s kit. This software is therefore particularly suitable for beginners who wish to start programming and development in Python and is therefore not at all suitable for development experts.

The user interface is isolated from all features that may distract beginners. It is a well-thought-out pedagogical course for beginners who want to develop in Python quickly, easily, and simply.

Advantage:

• IDE adapted for beginners’ learning
• Basic and functional user interface
• Does not require a large amount of memory to run

Disadvantage:

• If you are an experienced developer, this software is certainly not for you.
• Only basic functionalities

8.Eclipse + PyDev:

If you’ve spent any amount of time in the open-source community, you’ve heard about Eclipse. Available for Linux, Windows, and OS X at, Eclipse is the de-facto open-source IDE for Java development. It has a rich marketplace of extensions and add-ons, which makes Eclipse useful for a wide range of development activities.

One such extension is PyDev, which enables Python debugging, code completion, and an interactive Python console. Installing PyDev into Eclipse is easy: from Eclipse, select Help, Eclipse Marketplace, then search for PyDev. Click Install and restart Eclipse if necessary.

Which Python IDE is Right for You?

Only you can decide that, but here are some basic recommendations:

• New Python developers should try solutions with as few customizations as possible. The less gets in the way, the better.
• If you use text editors for other tasks (like web pages or documentation), look for code editor solutions.
• If you’re already developing other software, you may find it easier to add Python capabilities to your existing toolset.

Conclusion:

Python is one of the most well-known languages and perhaps even the most popular. As with most major languages, you have a multitude of useful, practical, and powerful IDEs, whether they are paid or free.

We can convert an integer data type using the python built-in str() function. This function takes any data type as an argument and converts it into a string. But we can also do it using the “%s” literal and using the .format() function.

How to convert an integer to a string in Python

Below is the list of possible ways to convert an integer to string in python:

1. Using str() function :

Syntax: str(integer_value)

Output:

2. Using “%s” keyword:

Syntax: “%s” % integer

Output:

3. Using .format() function:

Syntax: ‘{}’.format(integer)

Output:

4. Using f-string:

Syntax: f'{integer}’

Output:

Conclusion:

We have defined all methods of converting the integer data type to the string type. You can use one of them according to your requirement.

List is an important container and used almost in every code of day-day programming as well as web-development, more it is used, more is the requirement to master it and hence knowledge of its operations is necessary. This article focuses on one of the operations of getting the unique list from a list that contains a possible duplicated. Remove duplicates from list operation has large number of applications and hence, its knowledge is good to have.

How to Remove Duplicates From a Python List

Method 1 : Naive method

In Naive method, we simply traverse the list and append the first occurrence of the element in new list and ignore all the other occurrences of that particular element.

# Using Naive methods:

Output :

Method 2 : Using list comprehension

List comprehensions are Python functions that are used for creating new sequences (such as lists, tuple, etc.) using previously created sequence. This makes code more efficient and easy to understand. This method has working similar to the above method, but this is just a one-liner shorthand of longer method done with the help of list comprehension.

# Using list comprehension

Output :

Method 3 : Using set():

We can remove duplicates from a list using an inbuilt function called set(). The set() always return distinct elements. Therefore, we use the set() for removing duplicates.But the main and notable drawback of this approach is that the ordering of the element is lost in this particular method.

# Using set()

Output :

Method 4 : Using list comprehension + enumerate():

Enumerate can also be used for removing duplicates when used with the list comprehension.It basically looks for already occurred elements and skips adding them. It preserves the list ordering.

# Using list comprehension + enumerate()

Output :

Method 5 : Using collections.OrderedDict.fromkeys():

This is fastest method to achieve the particular task. It first removes the duplicates and returns a dictionary which has to be converted to list. This works well in case of strings also.

# Using collections.OrderedDict.fromkeys()

Output :

Conclusion :

In conclusion, now, you may know “how to remove duplicates from a list in python?“. There are different ways but the using collections.OrderedDict.fromkeys() method is the best in accordance with the programming efficiency of the computer.