Summary  
This chapter covers performing element-wise multiplication of each row in a matrix by a corresponding vector, emphasizing the requirement that the number of rows matches the vector length.

General domain of usage  
Financial data analysis

Let's consolidate acquired knowledge with a practical task!

> Note
>
> If you want to multiply each element of the row to a specific value (i.e., not one number for all elements), you need to have the condition: the number of rows of the matrix equals the multiplying vector length satisfied.

In the second part of R Introduction, you will learn about multi-dimensional built-in structures, such as matrices, data frames, and lists.

In the first section, you will learn the two-dimensional structure that is widely used in math. In R, this data type is used not only for math purposes but also has many real-life purposes.

In the second section, you will learn data frames - an 'upgraded' version of the matrix. Unlike matrix, the data frame may contain data of different types. Most real-life tables can be represented as data frames. You will learn how to create/manipulate data frames and extract necessary data.

In the final section, you will learn the lists in R. This data type works as vectors but may contain data of different types.

Month	Sofa	Armchair	Dining table	Dining chair	Bookshelf
March	16	21	30	23	10
April	40	39	13	21	16
May	11	21	36	32	16

Sales and Revenue

Lösning