Implemented new feature for Issue 2880

Added the ability to check the existance of a figure label instead of just figure number.

Author: jasonliw93

lib/matplotlib/pyplot.py

@@ -460,7 +460,9 @@ def gcf():
     else:
         return figure()
 
-fignum_exists = _pylab_helpers.Gcf.has_fignum
+def fignum_exists(num):
+    allLabels = get_figlabels()
+    return _pylab_helpers.Gcf.has_fignum(num) or num in allLabels 
 
 
 def get_fignums():

lib/matplotlib/tests/test_figure.py

@@ -32,6 +32,23 @@ def test_figure_label():
     assert_equal(plt.get_figlabels(), ['', 'today'])
 
 
+@cleanup
+def test_fignum_exists():
+    # pyplot figure creation, selection and closing with fignum_exists
+    plt.figure('one')
+    plt.figure(2)
+    plt.figure('three')
+    plt.figure()
+    assert_equal(plt.fignum_exists('one'), True)
+    assert_equal(plt.fignum_exists(2), True)
+    assert_equal(plt.fignum_exists('three'), True)
+    assert_equal(plt.fignum_exists(4), True)
+    plt.close('one')
+    plt.close(4)
+    assert_equal(plt.fignum_exists('one'), False)
+    assert_equal(plt.fignum_exists(4), False)
+
+
 @image_comparison(baseline_images=['figure_today'])
 def test_figure():
     # named figure support