用户定义的Python矩阵计算程序输入

Question

I have written up this "hard-coded" version of my end goal. As you can see, I have a specific value for n as well as pre-defined matrices X and Y. The program currently performs the calculations just fine but what I'm having trouble with is modifying it to accept user defined input for n, X, and Y and accurately perform the calculations based on what the user enters. I'm still getting used to Python and user input so any help with coding this would be greatly appreciated! I should also note that I'm trying to do this without NumPy for learning purposes. Thanks!

# Program to add two matrices
# using nested loop

n = 3

X = [[12,7,3],
    [4 ,5,6],
    [7 ,8,9]]

Y = [[5,8,1],
    [6,7,3],
    [4,5,9]]

result = [[0,0,0],
         [0,0,0],
         [0,0,0]]

# adds the matrices
# iterate through rows
for i in range(len(X)):
   # iterate through columns
   for j in range(len(X[0])):
       result[i][j] = X[i][j] + Y[i][j]

for r in result:
   print(r)


# subtracts the matrices
for i in range(len(X)):
   for j in range(len(X[0])):
       result[i][j] = X[i][j] - Y[i][j]

for r in result:
   print(r)

# multiplies the matrices
for i in range(len(X)):
   # iterate through columns
   for j in range(len(X[0])):
       result[i][j] = sum((X[i][v]*Y[v][j] for v in range(n)))

for r in result:
   print(r)

Answer 1

Maybe this will be helpful. First you get n from a user, and than read n number of rows for the X matrix. values in each row are separated by comma.

n  = int(input("Provide n: "))

X = [];

for rowi in range(n):
    row_list = list(map(float, input("row {}: ".format(rowi+1)).split(',')))
    X.append(row_list)

print(X)

Please note that this was tested in python 3.4 and there is no any error checking here. So probably you would need to add some conditions to check if user inputs are numbers, not strings for example, and that each row has same number of entries etc.

Answer 2

Since we know that matrx can be represented as nested Lists in Python,We can prompt for user input for each element.Elements in same row are first contained in a list called row[] which is then appended to the container list and hence we get lists inside container list and hence matrix.

#Prints the sum of matrix of orders mxn
first_row_count = int(input('Enter the number of rows of 1st matrix :'))
first_col_count = int(input('Enter the number of columns of 1st matrix :'))

second_row_count = int(input('Enter the number of rows of 1st matrix :'))
second_col_count = int(input('Enter the number of columns of 1st matrix :'))

first_Matrix =[]
second_matrix=[]

if(first_row_count == second_row_count) and (second_row_count == second_col_count):
    print('############Enter the elements of first Matrix#################')
    for i in range(0,first_row_count):
        row = []
        input_variable = None
        for j in range(0,first_col_count):
            input_variable = int(input('Enter the element at mat[{0}][{1}]'.format(i,j)))
            row.append(input_variable)
       first_Matrix.append(row) 

    print('############Enter the elements of second Matrix#################')    
    for i in range(0,second_row_count):
        row = []
        input_variable = None
        for j in range(0,second_col_count):
            input_variable = int(input('Enter the element at mat[{0}][{1}]'.format(i,j)))
            row.append(input_variable)
        second_matrix.append(row)          

    print('############Resultant Matrix#################')   
    result = [[first_Matrix[i][j] + second_matrix[i][j]  for j in range(len(first_Matrix[0]))] for i in range(len(first_Matrix))]
    for r in result:
           print(r)
else:
    print('------------The matrix of given orders are not compatible-----------------')    
print('########The Matrix Sum performed##################')