Question

Make a dictionary called plain with the key-value pairs ' \(a\) ' : 1 , ' \(b\) ' : 2 , and ' \(c\) ' : 3, and then print it.

Short answer

Create the dictionary with specified pairs and use `print(plain)` to display it.

Step-by-step solution

Defining the Dictionary

To begin, we need to create a dictionary and assign it to the variable named `plain`. This dictionary will contain keys and corresponding values. Keys should be enclosed in quotes if they are strings, and values are assigned using a colon. In this exercise, the dictionary will have the pairs `'a': 1`, `'b': 2`, and `'c': 3`.

Assigning Key-Value Pairs

Now, we manually input each key followed by its value into the dictionary. Type `plain = {'a': 1, 'b': 2, 'c': 3}`. Here, each key (like `'a'`, `'b'`, `'c'`) is a string, and each value (such as `1`, `2`, `3`) is an integer. Ensure that all keys and values are separated by commas.

Printing the Dictionary

After defining the dictionary, we need to display it. Use the `print` function to output the dictionary named `plain`. Type `print(plain)` and execute the command to view the contents of `plain`.

Key concepts

Dictionaries in Python

Dictionaries in Python are essential data structures used to store data in key-value pairs. They are highly flexible and allow you to store a vast range of data types. When working with dictionaries, it is key to understand how they differ from lists and other sequences. Unlike lists, dictionaries are indexed by keys, not positions. This makes them particularly useful for scenarios where you need to quickly retrieve, add, or manage data without worrying about its position.

• Dictionaries are created using curly braces { }.
• Each element in a dictionary has a unique key.
• Values in a dictionary can be of any data type, including numbers, lists, or even other dictionaries.

Creating a dictionary in Python is straightforward. You start by declaring the dictionary name and using curly braces to encapsulate key-value pairs. Each key-value pair is separated by a comma within the braces. It's that simple!

Key-Value Pairs

In Python dictionaries, data is organized into key-value pairs, serving as a map between each unique key and its corresponding value. This fundamental concept allows easy data storage and retrieval. A key-value pair is expressed as key: value. Keys must be unique within a dictionary, and they are typically strings or numbers. Values, in contrast, can be of any data type, making dictionaries versatile and powerful tools. Here are some things to remember about key-value pairs:

• Keys are immutable: Once set, they cannot be changed. This means you can use strings, numbers, or tuples as keys but not lists or dictionaries.
• Values can be anything: From integers to complex objects, any data type is valid for values.
• If a dictionary has duplicate keys, the last value assigned to a key will be the one stored.

Understanding key-value pairs allows one to unlock the true power of dictionaries in Python.

Printing in Python

The ability to display data is crucial, especially when debugging or presenting information. Python provides straightforward methods to print data, and when it comes to dictionaries, the print() function is frequently used. Using print() is simple: it outputs whatever is passed in between its parentheses. This works for all data types, including dictionaries. Here's what happens when you print a dictionary:

• The console will display the dictionary contents enclosed in curly braces.
• Each key-value pair will be shown, making it easy to visually verify the stored data.
• Keys and values are displayed in the same pattern as they appear within the dictionary.

Printing is not only a means to display data but also an invaluable tool to verify the contents and structure of your dictionaries as you develop your Python programs.