Remove list(zip(...)) when unnecessary.

anntzer · anntzer · commit 81b0efcf65c9 · 2017-12-26T20:31:03.000-08:00
Replace by zip(...) when the result is immediately unpacked.  Replace
by np.column_stack when operating on arrays or when the result will be
immediately converted to an array (e.g. by the Path constructor), as
column_stack is faster in these cases.

(This commit does not remove *all* instances of list(zip(...)).)
diff --git a/examples/api/collections.py b/examples/api/collections.py
@@ -30,16 +30,13 @@
 theta = np.linspace(0, 2*np.pi, nverts)
 xx = r * np.sin(theta)
 yy = r * np.cos(theta)
-spiral = list(zip(xx, yy))
+spiral = np.column_stack([xx, yy])
 
-# Make some offsets
 # Fixing random state for reproducibility
 rs = np.random.RandomState(19680801)
 
-
-xo = rs.randn(npts)
-yo = rs.randn(npts)
-xyo = list(zip(xo, yo))
+# Make some offsets
+xyo = rs.randn(npts, 2)
 
 # Make a list of colors cycling through the default series.
 colors = [colors.to_rgba(c)
@@ -109,11 +106,11 @@
 
 yy = np.linspace(0, 2*np.pi, nverts)
 ym = np.max(yy)
-xx = (0.2 + (ym - yy)/ym)**2 * np.cos(yy - 0.4)*0.5
+xx = (0.2 + (ym - yy) / ym) ** 2 * np.cos(yy - 0.4) * 0.5
 segs = []
 for i in range(ncurves):
     xxx = xx + 0.02*rs.randn(nverts)
-    curve = list(zip(xxx, yy*100))
+    curve = np.column_stack([xxx, yy * 100])
     segs.append(curve)
 
 col = collections.LineCollection(segs, offsets=offs)
diff --git a/examples/api/scatter_piecharts.py b/examples/api/scatter_piecharts.py
@@ -24,17 +24,17 @@
 # some points on a circle cos,sin
 x = [0] + np.cos(np.linspace(0, 2 * np.pi * r1, 10)).tolist()
 y = [0] + np.sin(np.linspace(0, 2 * np.pi * r1, 10)).tolist()
-xy1 = list(zip(x, y))
+xy1 = np.column_stack([x, y])
 s1 = np.abs(xy1).max()
 
 x = [0] + np.cos(np.linspace(2 * np.pi * r1, 2 * np.pi * r2, 10)).tolist()
 y = [0] + np.sin(np.linspace(2 * np.pi * r1, 2 * np.pi * r2, 10)).tolist()
-xy2 = list(zip(x, y))
+xy2 = np.column_stack([x, y])
 s2 = np.abs(xy2).max()
 
 x = [0] + np.cos(np.linspace(2 * np.pi * r2, 2 * np.pi, 10)).tolist()
 y = [0] + np.sin(np.linspace(2 * np.pi * r2, 2 * np.pi, 10)).tolist()
-xy3 = list(zip(x, y))
+xy3 = np.column_stack([x, y])
 s3 = np.abs(xy3).max()
 
 fig, ax = plt.subplots()
diff --git a/examples/event_handling/poly_editor.py b/examples/event_handling/poly_editor.py
@@ -167,10 +167,10 @@ def motion_notify_callback(self, event):
     theta = np.arange(0, 2*np.pi, 0.1)
     r = 1.5
 
-    xs = r*np.cos(theta)
-    ys = r*np.sin(theta)
+    xs = r * np.cos(theta)
+    ys = r * np.sin(theta)
 
-    poly = Polygon(list(zip(xs, ys)), animated=True)
+    poly = Polygon(np.column_stack([xs, ys]), animated=True)
 
     fig, ax = plt.subplots()
     ax.add_patch(poly)
diff --git a/examples/event_handling/trifinder_event_demo.py b/examples/event_handling/trifinder_event_demo.py
@@ -20,7 +20,7 @@ def update_polygon(tri):
         points = triang.triangles[tri]
     xs = triang.x[points]
     ys = triang.y[points]
-    polygon.set_xy(list(zip(xs, ys)))
+    polygon.set_xy(np.column_stack([xs, ys]))
 
 
 def motion_notify(event):
diff --git a/examples/lines_bars_and_markers/scatter_custom_symbol.py b/examples/lines_bars_and_markers/scatter_custom_symbol.py
@@ -11,7 +11,7 @@
 rx, ry = 3., 1.
 area = rx * ry * np.pi
 theta = np.arange(0, 2 * np.pi + 0.01, 0.1)
-verts = list(zip(rx / area * np.cos(theta), ry / area * np.sin(theta)))
+verts = np.column_stack([rx / area * np.cos(theta), ry / area * np.sin(theta)])
 
 x, y, s, c = np.random.rand(4, 30)
 s *= 10**2.
diff --git a/examples/lines_bars_and_markers/scatter_star_poly.py b/examples/lines_bars_and_markers/scatter_star_poly.py
@@ -21,7 +21,7 @@
 plt.subplot(322)
 plt.scatter(x, y, s=80, c=z, marker=(5, 0))
 
-verts = list(zip([-1., 1., 1., -1.], [-1., -1., 1., -1.]))
+verts = np.array([[-1, -1], [1, -1], [1, 1], [-1, -1]])
 plt.subplot(323)
 plt.scatter(x, y, s=80, c=z, marker=(verts, 0))
 # equivalent:
diff --git a/examples/shapes_and_collections/line_collection.py b/examples/shapes_and_collections/line_collection.py
@@ -72,7 +72,7 @@
 # See :class:`matplotlib.collections.LineCollection` for more information
 
 # Make a sequence of x,y pairs
-line_segments = LineCollection([list(zip(x, y)) for y in ys],
+line_segments = LineCollection([np.column_stack([x, y]) for y in ys],
                                linewidths=(0.5, 1, 1.5, 2),
                                linestyles='solid')
 line_segments.set_array(x)
diff --git a/examples/statistics/boxplot_demo.py b/examples/statistics/boxplot_demo.py
@@ -136,7 +136,7 @@
     for j in range(5):
         boxX.append(box.get_xdata()[j])
         boxY.append(box.get_ydata()[j])
-    boxCoords = list(zip(boxX, boxY))
+    boxCoords = np.column_stack([boxX, boxY])
     # Alternate between Dark Khaki and Royal Blue
     k = i % 2
     boxPolygon = Polygon(boxCoords, facecolor=boxColors[k])
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -3675,12 +3675,11 @@ def bxp(self, bxpstats, positions=None, widths=None, vert=True,
             final_meanprops.update(meanprops)
 
         def to_vc(xs, ys):
-            # convert arguments to verts and codes
-            verts = list(zip(xs, ys))
-            verts.append((0, 0))  # ignored
-            codes = [mpath.Path.MOVETO] + \
-                    [mpath.Path.LINETO] * (len(verts) - 2) + \
-                    [mpath.Path.CLOSEPOLY]
+            # convert arguments to verts and codes, append (0, 0) (ignored).
+            verts = np.append(np.column_stack([xs, ys]), [(0, 0)], 0)
+            codes = ([mpath.Path.MOVETO]
+                     + [mpath.Path.LINETO] * (len(verts) - 2)
+                     + [mpath.Path.CLOSEPOLY])
             return verts, codes
 
         def patch_list(xs, ys, **kwargs):
diff --git a/lib/matplotlib/bezier.py b/lib/matplotlib/bezier.py
@@ -168,24 +168,17 @@ def __init__(self, control_points):
         """
         _o = len(control_points)
         self._orders = np.arange(_o)
-        _coeff = BezierSegment._binom_coeff[_o - 1]
-
-        _control_points = np.asarray(control_points)
-        xx = _control_points[:, 0]
-        yy = _control_points[:, 1]
 
+        _coeff = BezierSegment._binom_coeff[_o - 1]
+        xx, yy = np.asarray(control_points).T
         self._px = xx * _coeff
         self._py = yy * _coeff
 
     def point_at_t(self, t):
         "evaluate a point at t"
-        one_minus_t_powers = np.power(1. - t, self._orders)[::-1]
-        t_powers = np.power(t, self._orders)
-
-        tt = one_minus_t_powers * t_powers
-        _x = sum(tt * self._px)
-        _y = sum(tt * self._py)
-
+        tt = ((1 - t) ** self._orders)[::-1] * t ** self._orders
+        _x = np.dot(tt, self._px)
+        _y = np.dot(tt, self._py)
         return _x, _y
 
 
@@ -245,7 +238,6 @@ def split_path_inout(path, inside, tolerence=0.01, reorder_inout=False):
     ctl_points, command = next(path_iter)
     begin_inside = inside(ctl_points[-2:])  # true if begin point is inside
 
-    bezier_path = None
     ctl_points_old = ctl_points
 
     concat = np.concatenate
@@ -259,16 +251,13 @@ def split_path_inout(path, inside, tolerence=0.01, reorder_inout=False):
         if inside(ctl_points[-2:]) != begin_inside:
             bezier_path = concat([ctl_points_old[-2:], ctl_points])
             break
-
         ctl_points_old = ctl_points
+    else:
+        raise ValueError("The path does not intersect with the patch")
 
-    if bezier_path is None:
-        raise ValueError("The path does not seem to intersect with the patch")
-
-    bp = list(zip(bezier_path[::2], bezier_path[1::2]))
-    left, right = split_bezier_intersecting_with_closedpath(bp,
-                                                            inside,
-                                                            tolerence)
+    bp = bezier_path.reshape((-1, 2))
+    left, right = split_bezier_intersecting_with_closedpath(
+        bp, inside, tolerence)
     if len(left) == 2:
         codes_left = [Path.LINETO]
         codes_right = [Path.MOVETO, Path.LINETO]
@@ -279,7 +268,7 @@ def split_path_inout(path, inside, tolerence=0.01, reorder_inout=False):
         codes_left = [Path.CURVE4, Path.CURVE4, Path.CURVE4]
         codes_right = [Path.MOVETO, Path.CURVE4, Path.CURVE4, Path.CURVE4]
     else:
-        raise ValueError()
+        raise AssertionError("This should never be reached")
 
     verts_left = left[1:]
     verts_right = right[:]
diff --git a/lib/matplotlib/offsetbox.py b/lib/matplotlib/offsetbox.py
@@ -398,7 +398,6 @@ def get_extent_offsets(self, renderer):
         ydescent = height - yoffsets[0]
         yoffsets = height - yoffsets
 
-        #w, h, xd, h_yd = whd_list[-1]
         yoffsets = yoffsets - ydescent
 
         return width + 2 * pad, height + 2 * pad, \
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -1357,7 +1357,7 @@ def get_path(self):
         xs = self.convert_xunits([xb1, xb2, xc2, xd2, x1, xd1, xc1, xb1])
         ys = self.convert_yunits([yb1, yb2, yc2, yd2, y1, yd1, yc1, yb1])
 
-        return Path(list(zip(xs, ys)), closed=True)
+        return Path(np.column_stack([xs, ys]), closed=True)
 
     def get_patch_transform(self):
         return transforms.IdentityTransform()
diff --git a/lib/matplotlib/sankey.py b/lib/matplotlib/sankey.py
@@ -704,7 +704,7 @@ def add(self, patchlabel='', flows=None, orientations=None, labels='',
                 [(Path.CLOSEPOLY, urpath[0][1])])
 
         # Create a patch with the Sankey outline.
-        codes, vertices = list(zip(*path))
+        codes, vertices = zip(*path)
         vertices = np.array(vertices)
 
         def _get_angle(a, r):
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -1705,7 +1705,8 @@ def test_scatter_marker():
     rx, ry = 3, 1
     area = rx * ry * np.pi
     theta = np.linspace(0, 2 * np.pi, 21)
-    verts = list(zip(np.cos(theta) * rx / area, np.sin(theta) * ry / area))
+    verts = np.column_stack([np.cos(theta) * rx / area,
+                             np.sin(theta) * ry / area])
     ax2.scatter([3, 4, 2, 6], [2, 5, 2, 3],
                 c=[(1, 0, 0), 'y', 'b', 'lime'],
                 s=[60, 50, 40, 30],
diff --git a/lib/matplotlib/tests/test_category.py b/lib/matplotlib/tests/test_category.py
@@ -239,7 +239,7 @@ def test_plot_update(self):
 
         labels = ['a', 'b', 'd', 'c']
         ticks = [0, 1, 2, 3]
-        unit_data = MockUnitData(list(zip(labels, ticks)))
+        unit_data = MockUnitData(zip(labels, ticks))
 
         self.axis_test(ax.yaxis, ticks, labels, unit_data)
 
diff --git a/lib/matplotlib/tests/test_streamplot.py b/lib/matplotlib/tests/test_streamplot.py
@@ -29,7 +29,7 @@ def test_startpoints():
     X, Y, U, V = velocity_field()
     start_x = np.linspace(X.min(), X.max(), 10)
     start_y = np.linspace(Y.min(), Y.max(), 10)
-    start_points = list(zip(start_x, start_y))
+    start_points = np.column_stack([start_x, start_y])
     plt.streamplot(X, Y, U, V, start_points=start_points)
     plt.plot(start_x, start_y, 'ok')
 
diff --git a/lib/matplotlib/tests/test_transforms.py b/lib/matplotlib/tests/test_transforms.py
@@ -197,7 +197,7 @@ def test_clipping_of_log():
                                  clip=(0, 0, 100, 100),
                                  simplify=False)
 
-    tpoints, tcodes = list(zip(*result))
+    tpoints, tcodes = zip(*result)
     assert_allclose(tcodes, [M, L, L, L, C])
 
 
diff --git a/lib/mpl_toolkits/axisartist/clip_path.py b/lib/mpl_toolkits/axisartist/clip_path.py
@@ -125,13 +125,13 @@ def clip_line_to_rect(xline, yline, bbox):
 
     #c_left = [((x, y), (a+90)%180-180) for (x, y, a) in c_left_ \
     #          if bbox.containsy(y)]
-    c_left = [((x, y), (a+90)%180-90) for (x, y, a) in c_left_ \
+    c_left = [((x, y), (a+90)%180-90) for (x, y, a) in c_left_
               if bbox.containsy(y)]
-    c_bottom = [((x, y), (90 - a)%180) for (y, x, a) in c_bottom_  \
+    c_bottom = [((x, y), (90 - a)%180) for (y, x, a) in c_bottom_
                 if bbox.containsx(x)]
-    c_right = [((x, y), (a+90)%180+90) for (x, y, a) in c_right_ \
+    c_right = [((x, y), (a+90)%180+90) for (x, y, a) in c_right_
                if bbox.containsy(y)]
-    c_top = [((x, y), (90 - a)%180+180) for (y, x, a) in c_top_ \
+    c_top = [((x, y), (90 - a)%180+180) for (y, x, a) in c_top_
              if bbox.containsx(x)]
 
     return list(zip(lx4, ly4)), [c_left, c_bottom, c_right, c_top]
diff --git a/lib/mpl_toolkits/axisartist/floating_axes.py b/lib/mpl_toolkits/axisartist/floating_axes.py
@@ -214,7 +214,7 @@ def get_line(self, axes):
                     top=("lat_lines0", 1))[self._side]
 
         xx, yy = self.grid_info[k][v]
-        return Path(list(zip(xx, yy)))
+        return Path(np.column_stack([xx, yy]))
 
 
 
diff --git a/lib/mpl_toolkits/axisartist/grid_helper_curvelinear.py b/lib/mpl_toolkits/axisartist/grid_helper_curvelinear.py
@@ -318,7 +318,7 @@ def get_line(self, axes):
         x, y = self.grid_info["line_xy"]
 
         if self._get_line_path is None:
-            return Path(list(zip(x, y)))
+            return Path(np.column_stack([x, y]))
         else:
             return self._get_line_path(axes, x, y)
 
diff --git a/lib/mpl_toolkits/mplot3d/art3d.py b/lib/mpl_toolkits/mplot3d/art3d.py
diff --git a/lib/mpl_toolkits/mplot3d/axes3d.py b/lib/mpl_toolkits/mplot3d/axes3d.py
diff --git a/lib/mpl_toolkits/mplot3d/proj3d.py b/lib/mpl_toolkits/mplot3d/proj3d.py
