(Python Beginner) Matrix printing in a function

Question

I've written a simple function as well as input for it, but I am not sure what to put into the "pass" for my desired output. Here is my code:

def print_matrix(matrix_in, rows, columns, matrix):
    pass

    def print_header(columns):
        line = "+"
        for i in range(columns):
            line += "---+"
        print(line)

matrix={(2, 2): 5, (1, 2): 4, (0, 1): 2, (0, 0): 1, (1, 1): 3, (2, 3): 6}
rows=3
columns=4
matrix="Matrix 1"

print_matrix(matrix, rows, columns, matrix)

For this desired output:

Matrix 1

+---+---+---+---+
|  1|  2|  0|  0|
+---+---+---+---+
|  0|  3|  4|  0|
+---+---+---+---+
|  0|  0|  5|  6|
+---+---+---+---+

Any help would be appreciated thank you.

Related: https://stackoverflow.com/questions/9535954/printing-lists-as-tabular-data — Antti Haapala -- Слава Україні, Oct 15 '17 at 17:47
First you should print the matrix *without* the lines, for that you need 2 for loops - outer for rows, inner for columns, then fetch the the value using `matrix_in.get((row, col), 0)`... — Antti Haapala -- Слава Україні, Oct 15 '17 at 17:49

score 0 · Answer 1 · answered Oct 15 '17 at 18:00

Not sure about dictionaries, with a list I would do

def print_matrix(matrix):
   for nr in range(len(matrix[:])):
      print '+----------------+'
      print '| '+' | '.join(str(i) for i in matrix[nr][:])+' |'
   print '+----------------+'
return

matrix = [[1,2,0,0],[0,3,4,0],[0,0,5,6]]
print_matrix(matrix)

score 0 · Accepted Answer · answered Oct 15 '17 at 18:03

Try this one:

def print_matrix(matrixIn, rows, columns, matrixName):
    print(matrixName + "\n")

    for i in range(rows):
        print("+---" * (rows+1) + "+")
        for j in range(columns):
            key = (i,j)
            value = matrixIn.get(key)
            if value is None:
                print("| ", 0, end="")
            else:
                print("| ", value, end="")
        print("|")
    print("+---" * (rows+1) + "+")

matrix={(2, 2): 5, (1, 2): 4, (0, 1): 2, (0, 0): 1, (1, 1): 3, (2, 3): 6}
rows=3
columns=4
matrixString="Matrix 1"

print_matrix(matrix, rows, columns, matrixString)

The result is:

Matrix 1

+---+---+---+---+
|  1|  2|  0|  0|
+---+---+---+---+
|  0|  3|  4|  0|
+---+---+---+---+
|  0|  0|  5|  6|
+---+---+---+---+

(Python Beginner) Matrix printing in a function

2 Answers2