In excel, which key can be used to input two vertical lines of absolute value? In English half-width state, just hold down shift and \ key ||. As for the difference between array and matrix, the elements in the array can be characters.

There can only be numbers in the matrix.

This is the most intuitive difference between the two. Because matrix is a mathematical concept (in linear algebra), array is a computer concept.

Have you ever seen the concept of array in pure mathematics? number

Because the knowledge of linear algebra is often used in computers (specifically in information science), the concept of matrix is cited. In terms of dimension, one-dimensional array is equivalent to vector, and two-dimensional array is equivalent to matrix.