# Python sorting matrix elements

Good day!

I wanted to understand the sorting of the elements of the matrix, which are located on the diagonals.

I'm new to Python, from reading the documentation and my code so far my head is spinning, so I ask for help.

There is a class of matrix, which describes the basic actions with the matrix. It is necessary to fasten here (preferably) the sorting of elements located on the diagonals of the matrix.

The class code that is currently available (python version 3.3):

``import random import operator import sys import unittest class MatrixError(Exception): """ An exception class for Matrix """ pass class Matrix(object): """ A simple Python matrix class with basic operations and operator overloading """ def __init__(self, m, n, init=True): if init: self.rows = [*n for x in range(m)] else: self.rows = [] self.m = m self.n = n def __getitem__(self, idx): return self.rows[idx] def __setitem__(self, idx, item): self.rows[idx] = item def __str__(self): s='\n'.join([' '.join([str(item) for item in row]) for row in self.rows]) return s + '\n' def __repr__(self): s=str(self.rows) rank = str(self.getRank()) rep="Matrix: \"%s\", rank: \"%s\"" % (s,rank) return rep def reset(self): """ Reset the matrix data """ self.rows = [[] for x in range(self.m)] def transpose(self): """ Transpose the matrix. Changes the current matrix """ self.m, self.n = self.n, self.m self.rows = [list(item) for item in zip(*self.rows)] def getTranspose(self): """ Return a transpose of the matrix without modifying the matrix itself """ m, n = self.n, self.m mat = Matrix(m, n) mat.rows = [list(item) for item in zip(*self.rows)] return mat def getRank(self): return (self.m, self.n) def __eq__(self, mat): """ Test equality """ return (mat.rows == self.rows) def __add__(self, mat): """ Add a matrix to this matrix and return the new matrix. Doesn't modify the current matrix """ if self.getRank() != mat.getRank(): raise (MatrixError, "Trying to add matrixes of varying rank!") ret = Matrix(self.m, self.n) for x in range(self.m): row = [sum(item) for item in zip(self.rows[x], mat[x])] ret[x] = row return ret def __sub__(self, mat): """ Subtract a matrix from this matrix and return the new matrix. Doesn't modify the current matrix """ if self.getRank() != mat.getRank(): raise (MatrixError, "Trying to add matrixes of varying rank!") ret = Matrix(self.m, self.n) for x in range(self.m): row = [item-item for item in zip(self.rows[x], mat[x])] ret[x] = row return ret def __mul__(self, mat): """ Multiple a matrix with this matrix and return the new matrix. Doesn't modify the current matrix """ matm, matn = mat.getRank() if (self.n != matm): raise (MatrixError, "Matrices cannot be multipled!") mat_t = mat.getTranspose() mulmat = Matrix(self.m, matn) for x in range(self.m): for y in range(mat_t.m): mulmat[x][y] = sum([item*item for item in zip(self.rows[x], mat_t[y])]) return mulmat def __iadd__(self, mat): """ Add a matrix to this matrix. This modifies the current matrix """ # Calls __add__ tempmat = self + mat self.rows = tempmat.rows[:] return self def __isub__(self, mat): """ Add a matrix to this matrix. This modifies the current matrix """ # Calls __sub__ tempmat = self - mat self.rows = tempmat.rows[:] return self def __imul__(self, mat): """ Add a matrix to this matrix. This modifies the current matrix """ # Possibly not a proper operation # since this changes the current matrix # rank as well... # Calls __mul__ tempmat = self * mat self.rows = tempmat.rows[:] self.m, self.n = tempmat.getRank() return self def save(self, filename): open(filename, 'w').write(str(self)) @classmethod def _makeMatrix(cls, rows): m = len(rows) n = len(rows) # Validity check if any([len(row) != n for row in rows[1:]]): raise (MatrixError, "inconsistent row length") mat = Matrix(m,n, init=False) mat.rows = rows return mat @classmethod def makeRandom(cls, m, n, low=0, high=10): """ Make a random matrix with elements in range (low-high) """ obj = Matrix(m, n, init=False) for x in range(m): obj.rows.append([random.randrange(low, high) for i in range(obj.n)]) return obj @classmethod def makeZero(cls, m, n): """ Make a zero-matrix of rank (mxn) """ rows = [*n for x in range(m)] return cls.fromList(rows) @classmethod def makeId(cls, m): """ Make identity matrix of rank (mxm) """ rows = [*m for x in range(m)] idx = 0 for row in rows: row[idx] = 1 idx += 1 return cls.fromList(rows) @classmethod def readStdin(cls): """ Read a matrix from standard input """ print ('Enter matrix row by row. Type "q" to quit') rows = [] while True: line = sys.stdin.readline().strip() if line=='q': break row = [int(x) for x in line.split()] rows.append(row) return cls._makeMatrix(rows) @classmethod def readGrid(cls, fname): """ Read a matrix from a file """ rows = [] for line in open(fname).readlines(): row = [int(x) for x in line.split()] rows.append(row) return cls._makeMatrix(rows) @classmethod def fromList(cls, listoflists): """ Create a matrix by directly passing a list of lists """ # Eg: Matrix.fromList([[1 2 3], [4,5,6], [7,8,9]]) rows = listoflists[:] return cls._makeMatrix(rows) class MatrixTests(unittest.TestCase): def testAdd(self): m1 = Matrix.fromList([[1, 2, 3], [4, 5, 6]]) m2 = Matrix.fromList([[7, 8, 9], [10, 11, 12]]) m3 = m1 + m2 self.assertTrue(m3 == Matrix.fromList([[8, 10, 12], [14,16,18]])) def testSub(self): m1 = Matrix.fromList([[1, 2, 3], [4, 5, 6]]) m2 = Matrix.fromList([[7, 8, 9], [10, 11, 12]]) m3 = m2 - m1 self.assertTrue(m3 == Matrix.fromList([[6, 6, 6], [6, 6, 6]])) def testMul(self): m1 = Matrix.fromList([[1, 2, 3], [4, 5, 6]]) m2 = Matrix.fromList([[7, 8], [10, 11], [12, 13]]) self.assertTrue(m1 * m2 == Matrix.fromList([[63, 69], [150, 165]])) self.assertTrue(m2*m1 == Matrix.fromList([[39, 54, 69], [54, 75, 96], [64, 89, 114]])) def testTranspose(self): m1 = Matrix.makeRandom(25, 30) zerom = Matrix.makeZero(25, 30) m2 = m1 + zerom m1.transpose() m1.transpose() self.assertTrue(m2 == m1) # Also test getTranspose m2 = m1.getTranspose() r2 = m2.getRank() self.assertTrue(r2==(30,25)) m2.transpose() self.assertTrue(m2 == m1) def testId(self): m1 = Matrix.makeId(10) m2 = Matrix.makeRandom(4, 10) m3 = m2*m1 self.assertTrue(m3 == m2) if __name__ == "__main__": unittest.main()` `
• Do you seriously think that someone will read this? - skegg
• Maybe while I finish the code, someone will express their opinion. Thanks for stopping by. - sventhevith
• What sorting should look like with tz user? Call the sort method of the matrix object, which returns a sorted list of elements on the diagonal? - fogbit
• To work with matrices, use NumPy rather than write bikes. - skegg
• fogbit, to a point. The user calls the sort method and gets a sorted sequence of elements. mikillskegg, I would gladly use NumPy or SciPy if these calculations were needed personally for me, or, say, at work for a large number of users. and so ... the school requires bicycles. - sventhevith

` `from random import randrange as rnd nc = 10 nr = 10 a = [[rnd(10) for c in range(nc)] for r in range(nr)] for r in a: print(*r) for k in range(nr-1): for i in range(nc-1): if a[i][i] < a[i+1][i+1]: a[i][i],a[i+1][i+1] = a[i+1][i+1],a[i][i] print() for r in a: print(*r)` `