Merge pull request matplotlib#2461 from tacaswell/new_style_format_str

Added a new style string Formatter.

Author: pelson

doc/api/api_changes.rst

@@ -103,8 +103,9 @@ original location:
 * Added the rcParam `axes.fromatter.useoffset` to control the default value
   of `useOffset` in `ticker.ScalarFormatter`
 
-
-
+* Added `Formatter` sub-class `StrMethodFormatter` which
+  does the exact same thing as `FormatStrFormatter`, but for new-style
+  formatting strings.
 
 .. _changes_in_1_3:
 

doc/users/whats_new.rst

@@ -55,9 +55,9 @@ He also increased the performance for all of these functions and plot types.
 
 Support for detrending and windowing 2D arrays in mlab
 ``````````````````````````````````````````````````````
-Todd Jennings added support for 2D arrays in the 
+Todd Jennings added support for 2D arrays in the
 :func:`~matplotlib.mlab.detrend_mean`, :func:`~matplotlib.mlab.detrend_none`,
-and :func:`~matplotlib.mlab.detrend`, as well as adding 
+and :func:`~matplotlib.mlab.detrend`, as well as adding
 :func:`~matplotlib.mlab.apply_window` which support windowing 2D arrays.
 
 Support for strides in mlab
@@ -68,6 +68,11 @@ strides to create memory-efficient 2D arrays.  This includes
 array, and :func:`~matplotlib.mlab.stride_windows`, which uses a moving window
 to create a 2D array from a 1D array.
 
+Formatter for new-style formatting strings
+``````````````````````````````````````````
+Added `FormatStrFormatterNewStyle` which does the same job as
+`FormatStrFormatter`, but accepts new-style formatting strings
+instead of printf-style formatting strings
 
 Date handling
 -------------

lib/matplotlib/tests/test_ticker.py

@@ -7,6 +7,7 @@
 from numpy.testing import assert_almost_equal
 import numpy as np
 import matplotlib
+
 import matplotlib.ticker as mticker
 
 
@@ -24,7 +25,7 @@ def test_MaxNLocator():
 
 def test_LinearLocator():
     loc = mticker.LinearLocator(numticks=3)
-    test_value = np.array([-0.8, -0.3,  0.2])
+    test_value = np.array([-0.8, -0.3, 0.2])
     assert_almost_equal(loc.tick_values(-0.8, 0.2), test_value)
 
 
@@ -57,6 +58,16 @@ def test_use_offset():
             nose.tools.assert_equal(use_offset, tmp_form.get_useOffset())
 
 
+def test_formatstrformatter():
+    # test % style formatter
+    tmp_form = mticker.FormatStrFormatter('%05d')
+    nose.tools.assert_equal('00002', tmp_form(2))
+
+    # test str.format() style formatter
+    tmp_form = mticker.StrMethodFormatter('{x:05d}')
+    nose.tools.assert_equal('00002', tmp_form(2))
+
+
 if __name__ == '__main__':
     import nose
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)

lib/matplotlib/ticker.py

@@ -292,7 +292,7 @@ def __call__(self, x, pos=None):
 
 class FormatStrFormatter(Formatter):
     """
-    Use a format string to format the tick
+    Use an old-style ('%' operator) format string to format the tick
     """
     def __init__(self, fmt):
         self.fmt = fmt
@@ -302,6 +302,19 @@ def __call__(self, x, pos=None):
         return self.fmt % x
 
 
+class StrMethodFormatter(Formatter):
+    """
+    Use a new-style format string (as used by `str.format()`)
+    to format the tick.  The field formatting must be labeled `x`.
+    """
+    def __init__(self, fmt):
+        self.fmt = fmt
+
+    def __call__(self, x, pos=None):
+        'Return the format for tick val *x* at position *pos*'
+        return self.fmt.format(x=x)
+
+
 class OldScalarFormatter(Formatter):
     """
     Tick location is a plain old number.