编辑代码

# 创建矩阵A，按列填充
A <- matrix(1:20, nrow = 4, ncol = 5, byrow = FALSE)
print("Matrix A:")
print(A)

# 创建矩阵B，按行填充
B <- matrix(1:20, nrow = 4, ncol = 5, byrow = TRUE)
print("Matrix B:")
print(B)

# C = A + B
C_add <- A + B
print("Matrix C (A + B):")
print(C_add)

# C = A * B (元素逐个相乘)
C_multiply <- A * B
print("Matrix C (A * B):")
print(C_multiply)

# D 是由 A 的前3行和前3列构成的矩阵
D <- A[1:3, 1:3]
print("Matrix D (first 3 rows and first 3 columns of A):")
print(D)

# E 是由矩阵 B 的各列构成的矩阵，但不包含第三列
E <- B[, -3]
print("Matrix E (B without the third column):")
print(E)