## Creating an Array of Arrays in Python using NumPy

Arrays are an essential part of any programming language and are used for storing and manipulating data. Numpy is a popular library in Python used for scientific computing and is widely used in data science.

NumPy provides a variety of useful functions for creating arrays of all types, including arrays of arrays. In this article, we will be discussing how to create an array of arrays in Python using NumPy.

### Method 1: Combine Individual Arrays

The first method to create an array of arrays in Python using NumPy is to combine individual arrays.

This method is straightforward and involves combining several individual arrays into a larger array. Let’s take a look at how we can do this.

First, we need to create individual arrays:

```
import numpy as np
arr1 = np.array([1, 2, 3])
arr2 = np.array([4, 5, 6])
arr3 = np.array([7, 8, 9])
```

Next, we can use NumPy’s `concatenate()`

function to join the individual arrays:

```
array_of_arrays = np.concatenate((arr1, arr2, arr3))
```

This will create a 1-dimensional array. To convert it into an array of arrays, we can use NumPy’s `reshape()`

function:

```
array_of_arrays = array_of_arrays.reshape((3, 3))
```

This will create an array of arrays with 3 rows and 3 columns.

### Method 2: Create Array of Arrays Directly

The second method to create an array of arrays in Python using NumPy is to create the array of arrays directly. This method is useful when we need to create an array of arrays with a specific shape.

Here’s an example:

```
array_of_arrays = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
```

This will create an array of arrays with 3 rows and 3 columns.

## Examples of Creating Array of Arrays in Python using NumPy

### Method 1: Combine Individual Arrays

Suppose we have three individual arrays representing different branches of a company’s revenue.

We want to create an array of arrays to store this information. Here’s how we can do this:

```
import numpy as np
branch1 = np.array([10000, 15000, 20000])
branch2 = np.array([12000, 18000, 22000])
branch3 = np.array([8000, 12000, 17000])
array_of_arrays = np.concatenate((branch1, branch2, branch3)).reshape((3, 3))
print(array_of_arrays)
```

### Output:

```
[[10000 15000 20000]
[12000 18000 22000]
[ 8000 12000 17000]]
```

This will create an array of arrays with 3 rows and 3 columns, representing the revenue of three different branches of the company.

### Method 2: Create Array of Arrays Directly

Suppose we want to create an array of arrays to store the scores of three students in three different subjects.

Here’s how we can do this:

```
import numpy as np
array_of_arrays = np.array([[85, 90, 95], [80, 85, 90], [90, 95, 100]])
print(array_of_arrays)
```

### Output:

```
[[ 85 90 95]
[ 80 85 90]
[ 90 95 100]]
```

This will create an array of arrays with 3 rows and 3 columns, representing the scores of three students in three different subjects.

## Conclusion

In this article, we discussed how to create an array of arrays in Python using NumPy. We covered two methods for creating an array of arrays – combining individual arrays and creating the array of arrays directly. We also provided examples to illustrate these methods.

Hopefully, this article has provided a clear understanding of how to create an array of arrays in Python using NumPy, which can be useful for various applications in data science and scientific computing.

## Retrieving Information from Array of Arrays in Python using NumPy

Now that we know how to create an array of arrays in Python using NumPy, let’s explore how we can extract information from these arrays. In this article, we will cover three methods for retrieving information from an array of arrays in Python using NumPy: retrieving dimensions using the `shape()`

function, retrieving total values using the `size()`

function, and accessing elements using bracket notation.

### Retrieving Dimensions using shape() function

The `shape()`

function is used to retrieve the dimensions of an array. When applied to an array of arrays, it returns a tuple that represents the number of rows and columns in the array.

### Consider the following example:

```
import numpy as np
array_of_arrays = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
print(array_of_arrays.shape)
```

### Output:

```
(3, 3)
```

Here, `shape()`

returns a tuple with two values – the number of rows and columns in the array. We can use indexing to retrieve individual values from the tuple:

```
import numpy as np
array_of_arrays = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
rows, columns = array_of_arrays.shape
print('Number of rows:', rows)
print('Number of columns:', columns)
```

### Output:

```
Number of rows: 3
Number of columns: 3
```

This will print the number of rows and columns in the array.

### Retrieving Total Values using size() function

The `size()`

function returns the total number of elements in an array. When applied to an array of arrays, it returns the total number of elements in all the arrays combined.

### Consider the following example:

```
import numpy as np
array_of_arrays = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
print(array_of_arrays.size)
```

### Output:

```
9
```

Here, `size()`

returns the total number of elements in the array.

### Accessing Elements using bracket notation

We can access individual elements in an array of arrays using bracket notation. Bracket notation involves specifying the index of the element we want to retrieve for each dimension of the array.

### Consider the following example:

```
import numpy as np
array_of_arrays = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]])
print(array_of_arrays[1, 2])
```

### Output:

```
6
```

Here, we used bracket notation to access the element in the second row and third column of the array of arrays. Note that indexing in Python starts at 0, so the first row and column have an index of 0.

## Additional Resources for Working with Arrays in Python using NumPy

NumPy provides a wide range of functions for manipulating arrays. Here are some additional resources that can be helpful when working with arrays in Python using NumPy:

- NumPy documentation: The official documentation for NumPy provides detailed information on all the functions and methods available in the library.
- NumPy tutorial: The NumPy tutorial is a comprehensive guide to NumPy that covers everything from the basics to advanced topics.
- NumPy for Data Science: This tutorial series covers NumPy as well as other important Python libraries for data science, such as Pandas and Matplotlib.
- NumPy cheat sheet: This cheat sheet provides a quick reference guide to NumPy functions and methods.

This is a great resource for learning more about NumPy and its capabilities.

## Conclusion

In this article, we discussed three methods for retrieving information from an array of arrays in Python using NumPy: retrieving dimensions using the `shape()`

function, retrieving total values using the `size()`

function, and accessing elements using bracket notation. We also provided additional resources for working with arrays in Python using NumPy, including the official documentation, tutorials, and a cheat sheet.

With these tools and techniques, you can start working with arrays in Python using NumPy and perform various data analysis tasks.

In this article, we explored how to retrieve information from an array of arrays in Python using NumPy. We covered three methods: retrieving dimensions using the `shape()`

function, retrieving total values using the `size()`

function, and accessing elements using bracket notation.

We also provided additional resources for working with arrays in Python using NumPy. Having a solid understanding of how to retrieve information from arrays of arrays is crucial in data science and scientific computing. With these tools and techniques, you can start working with arrays in Python using NumPy and perform various data analysis tasks efficiently.