Sparsify long-range yearly return labels with a ceiling-based step

quantstats/_plotting/core.py

@@ -260,22 +260,21 @@ def plot_returns_bars(
 
     # Format x-axis labels
     try:
-        ax.set_xticklabels(df.index.year)
-        years = sorted(list(set(df.index.year)))
+        years = [str(year) for year in df.index.year]
     except AttributeError:
-        ax.set_xticklabels(df.index)
-        years = sorted(list(set(df.index)))
+        years = [str(label) for label in df.index]
+
+    tick_labels = years
 
     # ax.fmt_xdata = _mdates.DateFormatter('%Y-%m-%d')
     # years = sorted(list(set(df.index.year)))
 
     # Reduce label density for long time series
     if len(years) > 10:
-        mod = int(len(years) / 10)
-        _plt.xticks(
-            _np.arange(len(years)),
-            [str(year) if not i % mod else "" for i, year in enumerate(years)],
-        )
+        step = max(1, int(_np.ceil(len(years) / 10)))
+        tick_labels = [label if not i % step else "" for i, label in enumerate(years)]
+
+    ax.set_xticklabels(tick_labels)
 
     # rotate and align the tick labels so they look better
     fig.autofmt_xdate()

tests/test_plots.py

@@ -54,6 +54,21 @@ def test_yearly_returns(self, sample_returns):
         fig = plots.yearly_returns(sample_returns, show=False)
         assert fig is not None
 
+    def test_yearly_returns_sparsifies_labels_for_long_ranges(self):
+        """Test yearly returns uses sparser year labels once the range exceeds 10 years."""
+        np.random.seed(7)
+        dates = pd.date_range("2010-01-01", periods=365 * 12, freq="D")
+        returns = pd.Series(np.random.randn(len(dates)) * 0.01, index=dates, name="Strategy")
+        benchmark = pd.Series(np.random.randn(len(dates)) * 0.008, index=dates, name="Benchmark")
+
+        fig = plots.yearly_returns(returns, benchmark=benchmark, show=False)
+        labels = [tick.get_text() for tick in fig.axes[0].get_xticklabels()]
+        non_empty_labels = [label for label in labels if label]
+
+        assert len(labels) == 12
+        assert len(non_empty_labels) == 6
+        assert non_empty_labels == ["2010", "2012", "2014", "2016", "2018", "2020"]
+
     def test_histogram(self, sample_returns, sample_benchmark):
         """Test histogram plot."""
         fig = plots.histogram(sample_returns, sample_benchmark, show=False)