spiral matrix and prime factors exercise

python/spiral-matrix/.exercism/metadata.json

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+{"track":"python","exercise":"spiral-matrix","id":"e351192377fc41329076c9d6636ef233","url":"https://exercism.io/my/solutions/e351192377fc41329076c9d6636ef233","handle":"Xevion","is_requester":true,"auto_approve":false}

python/spiral-matrix/README.md

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+# Spiral Matrix
+
+Given the size, return a square matrix of numbers in spiral order.
+
+The matrix should be filled with natural numbers, starting from 1
+in the top-left corner, increasing in an inward, clockwise spiral order,
+like these examples:
+
+###### Spiral matrix of size 3
+
+```text
+1 2 3
+8 9 4
+7 6 5
+```
+
+###### Spiral matrix of size 4
+
+```text
+ 1  2  3 4
+12 13 14 5
+11 16 15 6
+10  9  8 7
+```
+
+## Exception messages
+
+Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
+indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
+every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
+a message.
+
+To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
+`raise Exception`, you should write:
+
+```python
+raise Exception("Meaningful message indicating the source of the error")
+```
+
+## Running the tests
+
+To run the tests, run the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)):
+
+- Python 2.7: `py.test spiral_matrix_test.py`
+- Python 3.4+: `pytest spiral_matrix_test.py`
+
+Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
+`python -m pytest spiral_matrix_test.py`
+
+### Common `pytest` options
+
+- `-v` : enable verbose output
+- `-x` : stop running tests on first failure
+- `--ff` : run failures from previous test before running other test cases
+
+For other options, see `python -m pytest -h`
+
+## Submitting Exercises
+
+Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/spiral-matrix` directory.
+
+You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
+
+For more detailed information about running tests, code style and linting,
+please see [Running the Tests](http://exercism.io/tracks/python/tests).
+
+## Source
+
+Reddit r/dailyprogrammer challenge #320 [Easy] Spiral Ascension. [https://www.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/](https://www.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/)
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

python/spiral-matrix/spiral_matrix.py

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+# Two lines, dude. ez.
+def spiral_matrix(size):
+    return [] if size < 1 else Matrix(size).matrix
+
+# Class for a pathfinding based spiral generation
+class Matrix:
+    def __init__(self, size):
+        self.size = size
+        self.matrix = [[None for y in range(size)] for x in range(size)]
+        self.i = 1
+        self.cur = (0, 0)
+        self.cardinals = [(0, 1), (1, 0), (-1, 0), (0, -1)]
+        self.dir_index = 0
+        self.loop()
+
+    # Loop that builds the spiral matrix
+    def loop(self):
+        # While the current number is less than the maximum number
+        while self.i < (self.size ** 2):
+            # If the next position is not valid, turn
+            if not self.valid(self.nextpos):
+                self.dir_index = (self.dir_index + 1) % 4
+            else:
+                self.access()
+                self.cur = self.nextpos
+        self.access()
+    
+    # Access a position and increment the counter
+    def access(self):
+        self.matrix[self.cur[0]][self.cur[1]] = self.i
+        self.i += 1
+
+    # Just the current direction (as an offset)
+    @property
+    def direction(self):
+        return self.cardinals[self.dir_index]
+
+    # Next position for access based on the current direction
+    @property
+    def nextpos(self):
+        return (self.cur[0] + self.direction[0], self.cur[1] + self.direction[1])
+
+    # Determine whether a position is valid to be approached
+    def valid(self, pos):
+        return self.validxy(pos[0], pos[1]) and not self.matrix[pos[0]][pos[1]]
+
+    # Determine whether a position is 
+    def validxy(self, x, y):
+        return x >= 0 and x < self.size and y >= 0 and y < self.size
+    
+    # Printable Matrix with proper character space justification
+    def __repr__(self):
+        return '\n'.join([' '.join(map(lambda item : str(item or '?').rjust(len(str(self.size ** 2))), sub)) for sub in self.matrix])

python/spiral-matrix/spiral_matrix_test.py

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+import unittest
+
+from spiral_matrix import spiral_matrix
+
+
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.1.0
+
+
+class SpiralMatrixTest(unittest.TestCase):
+    def test_empty_spiral(self):
+        self.assertEqual(spiral_matrix(0), [
+        ])
+
+    def test_trivial_spiral(self):
+        self.assertEqual(spiral_matrix(1), [
+            [1]
+        ])
+
+    def test_spiral_of_size_2(self):
+        self.assertEqual(spiral_matrix(2), [
+            [1, 2],
+            [4, 3]
+        ])
+
+    def test_spiral_of_size_3(self):
+        self.assertEqual(spiral_matrix(3), [
+            [1, 2, 3],
+            [8, 9, 4],
+            [7, 6, 5]
+        ])
+
+    def test_spiral_of_size_4(self):
+        self.assertEqual(spiral_matrix(4), [
+            [1,  2,  3,  4],
+            [12, 13, 14, 5],
+            [11, 16, 15, 6],
+            [10, 9,  8,  7]
+        ])
+
+    def test_spiral_of_size_5(self):
+        self.assertEqual(spiral_matrix(5), [
+            [1,  2,  3,  4,  5],
+            [16, 17, 18, 19, 6],
+            [15, 24, 25, 20, 7],
+            [14, 23, 22, 21, 8],
+            [13, 12, 11, 10, 9]
+        ])
+
+
+if __name__ == '__main__':
+    unittest.main()