Merge pull request #102 from dsimandl/master

The loops in the rotate90CW function and the __str__ function are now....
careercup · Feb 23, 2015 · 2eb334c · 2eb334c
2 parents 6d00f75 + e53a408
commit 2eb334c
Showing 1 changed file with 14 additions and 21 deletions.
diff --git a/python/Chapter 1/Question1_6/ChapQ1.6.py b/python/Chapter 1/Question1_6/ChapQ1.6.py
@@ -9,29 +9,22 @@ def __init__(self, matrix):
         self.matrix = matrix
 
     def __str__(self):
-        rowstring=""
-        for row in self.matrix:
-            rowstring = rowstring + "["
-            for cell in row:
-                rowstring = rowstring + " " + str(cell) + " "
-            rowstring = rowstring + "]\n"            
-        return rowstring
+
+        # Iterating over rows and the matrix via a generator,
+        # and joining the cell and then row into the final string output
+        return ''.join("%s%s%s" % ("[", ''.join("%s%s%s" % (" ", str(cell), " ")
+                                                for cell in row), "]\n") for row in self.matrix)
 
     def rotate90CW(self):
-        #strategy is to make what are now rows into columns, and reverse the order, which mimics the effect of rotation on the matrix.
-        columnlist=[]
-        for row in self.matrix:
-            #set up a list for columns
-            columnlist.append([])        
-        for row in self.matrix:
-            columnindex=0
-            for cell in row:
-                columnlist[columnindex].append(cell)
-                columnindex += 1
-        newmatrix=[]
-        for col in columnlist:
-            newmatrix.append(reversed(col))
-        self.matrix=newmatrix
+        # strategy is to make what are now rows into columns, and reverse the order,
+        # which mimics the effect of rotation on the matrix.
+        # This creates our empty list of columns by the length of the original matrix
+        columnlist = [[] for i in range(len(self.matrix))]
+        # Now this iterates through the rows and columns and appends those to the new columnlist
+        [[columnlist[i].append(row[i]) for i in range(len(row))] for row in self.matrix]
+        # reverses the new column list to get the order that is wanted, and assigned back to the original matrix
+        self.matrix = [reversed(col) for col in columnlist]
+
 #testing
 
 mat1= MatrixProcessor([[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16]])