PEP8ify some variable names.

nrows/ncols is already used as parameter names in subplots() so
standardizing on them seems good enough.

Note that the docstring of SubplotBase was previously incorrect:
one didn't need `numRows <= numCols <= plotNum < 10`, just that all
three be single-digit.

lib/matplotlib/axes/_axes.py

@@ -5634,12 +5634,11 @@ def _pcolorargs(funcname, *args, allmatch=False):
 
         if len(args) == 1:
             C = np.asanyarray(args[0])
-            numRows, numCols = C.shape
+            nrows, ncols = C.shape
             if allmatch:
-                X, Y = np.meshgrid(np.arange(numCols), np.arange(numRows))
+                X, Y = np.meshgrid(np.arange(ncols), np.arange(nrows))
             else:
-                X, Y = np.meshgrid(np.arange(numCols + 1),
-                                   np.arange(numRows + 1))
+                X, Y = np.meshgrid(np.arange(ncols + 1), np.arange(nrows + 1))
             C = cbook.safe_masked_invalid(C)
             return X, Y, C
 
@@ -5659,7 +5658,7 @@ def _pcolorargs(funcname, *args, allmatch=False):
                     X = X.data  # strip mask as downstream doesn't like it...
                 if isinstance(Y, np.ma.core.MaskedArray):
                     Y = Y.data
-            numRows, numCols = C.shape
+            nrows, ncols = C.shape
         else:
             raise TypeError(
                 'Illegal arguments to %s; see help(%s)' % (funcname, funcname))
@@ -5677,12 +5676,12 @@ def _pcolorargs(funcname, *args, allmatch=False):
                 'Incompatible X, Y inputs to %s; see help(%s)' % (
                 funcname, funcname))
         if allmatch:
-            if (Nx, Ny) != (numCols, numRows):
+            if (Nx, Ny) != (ncols, nrows):
                 raise TypeError('Dimensions of C %s are incompatible with'
                                 ' X (%d) and/or Y (%d); see help(%s)' % (
                                     C.shape, Nx, Ny, funcname))
         else:
-            if not (numCols in (Nx, Nx - 1) and numRows in (Ny, Ny - 1)):
+            if not (ncols in (Nx, Nx - 1) and nrows in (Ny, Ny - 1)):
                 raise TypeError('Dimensions of C %s are incompatible with'
                                 ' X (%d) and/or Y (%d); see help(%s)' % (
                                     C.shape, Nx, Ny, funcname))

lib/matplotlib/axes/_subplots.py

@@ -17,16 +17,19 @@ class SubplotBase:
 
     def __init__(self, fig, *args, **kwargs):
         """
-        *fig* is a :class:`matplotlib.figure.Figure` instance.
-
-        *args* is the tuple (*numRows*, *numCols*, *plotNum*), where
-        the array of subplots in the figure has dimensions *numRows*,
-        *numCols*, and where *plotNum* is the number of the subplot
-        being created.  *plotNum* starts at 1 in the upper left
-        corner and increases to the right.
-
-        If *numRows* <= *numCols* <= *plotNum* < 10, *args* can be the
-        decimal integer *numRows* * 100 + *numCols* * 10 + *plotNum*.
+        Parameters
+        ----------
+        fig : `matplotlib.figure.Figure`
+
+        *args : tuple (*nrows*, *ncols*, *index*) or int
+            The array of subplots in the figure has dimensions ``(nrows,
+            ncols)``, and *index* is the index of the subplot being created.
+            *index* starts at 1 in the upper left corner and increases to the
+            right.
+
+            If *nrows*, *ncols*, and *index* are all single digit numbers, then
+            *args* can be passed as a single 3-digit number (e.g. 234 for
+            (2, 3, 4)).
         """
 
         self.figure = fig

lib/mpl_toolkits/axes_grid1/axes_divider.py

@@ -350,15 +350,17 @@ def __init__(self, fig, *args, horizontal=None, vertical=None,
         """
         Parameters
         ----------
-        fig : :class:`matplotlib.figure.Figure`
-        *args : tuple (*numRows*, *numCols*, *plotNum*)
-            The array of subplots in the figure has dimensions *numRows*,
-            *numCols*, and *plotNum* is the number of the subplot
-            being created.  *plotNum* starts at 1 in the upper left
-            corner and increases to the right.
-
-            If *numRows* <= *numCols* <= *plotNum* < 10, *args* can be the
-            decimal integer *numRows* * 100 + *numCols* * 10 + *plotNum*.
+        fig : `matplotlib.figure.Figure`
+
+        *args : tuple (*nrows*, *ncols*, *index*) or int
+            The array of subplots in the figure has dimensions ``(nrows,
+            ncols)``, and *index* is the index of the subplot being created.
+            *index* starts at 1 in the upper left corner and increases to the
+            right.
+
+            If *nrows*, *ncols*, and *index* are all single digit numbers, then
+            *args* can be passed as a single 3-digit number (e.g. 234 for
+            (2, 3, 4)).
         """
 
         self.figure = fig