Скачать или смотреть Creating a Dynamic Two-Dimensional Array as a Global Variable in Python

Learn how to declare a dynamic two-dimensional array in Python as a global variable and resize it based on user input.
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Creating a Dynamic Two-Dimensional Array as a Global Variable in Python

In Python, working with matrices or two-dimensional arrays can be a bit challenging, especially when you want the dimensions of these arrays to be determined at runtime. This flexibility allows programmers to create data structures that can adapt based on user input. In this guide, we'll explore how to create and manage a global variable that functions as a two-dimensional array with dynamically assigned dimensions.

The Challenge

You may find yourself in a situation where you need to create a two-dimensional array but want to define its size based on user input. The problem here is twofold:

How to declare the two-dimensional array initially?

How to resize the array as needed?

Let’s break down the solution!

Step 1: Declaring a Two-Dimensional Array

To get started, we will initialize a two-dimensional array. In Python, this can be easily done using a list of lists. Here’s how to declare it:

[[See Video to Reveal this Text or Code Snippet]]

Explanation

The line a = [[]] creates an empty two-dimensional array, represented as a list containing another empty list. When printed, it appears as [[]], which signifies it holds one row but no columns yet.

Accessing Elements

To access specific elements in this array format, you can use indexing like so:

[[See Video to Reveal this Text or Code Snippet]]

Here, y represents the row index, and x represents the column index.

Step 2: Dynamic Resizing of the Array

When your application requires a change in size—perhaps based on user input—you can easily modify the two-dimensional array using the append method.

Example of Resizing

Let’s assume users input the number of rows and columns they wish to work with. Here’s a simple approach to adjust the array dynamically:

[[See Video to Reveal this Text or Code Snippet]]

Breakdown of the Resize Function

Global Keyword: The global a statement allows us to modify the global variable a.

Matrix Creation: The [[0]*cols for _ in range(rows)] syntax initializes a 2D array (or matrix) with rows and cols dimensions, filling it with zeros.

Accessing Newly Created Elements

Once resized, you can still access elements in the same manner using a[y][x].

Conclusion

The ability to create and resize a dynamic two-dimensional array as a global variable in Python opens many possibilities for your programming projects. This functionality allows your application to be more user-friendly and adaptable to varying data structures as needed.

Now that you understand how to declare and manage a dynamic two-dimensional array, you can apply this knowledge to your specific projects. Happy coding!