Fix geom_histogram and mapping to the weight aesthetic

Also fixes the same problem for geom_bindot.

fixes #936

Author: has2k1

doc/changelog.qmd

@@ -126,6 +126,9 @@ title: Changelog
   the themeables. This affected `theme_xkcd` and any `theme` settings that tried to slide the
   text / background into the panel.
 
+- Fixed bug in [](:class:`~plotnine.geom_histogram`) where mapping to the `weight` aesthetic
+  lead to an error. {{< issue 936 >}}
+
 ## v0.14.5
 (2025-01-02)
 [![](https://zenodo.org/badge/DOI/10.5281/zenodo.14587381.svg)](https://doi.org/10.5281/zenodo.14587381)

plotnine/stats/binning.py

@@ -165,7 +165,10 @@ def assign_bins(
     if weight is None:
         weight = np.ones(len(x))
     else:
-        weight = np.asarray(weight)
+        # If weight is a dtype that isn't writeable
+        # and does not own it's memory. Using a list
+        # as an intermediate easily solves this.
+        weight = np.array(list(weight))
         weight[np.isnan(weight)] = 0
 
     bin_idx = pd.cut(

plotnine/stats/stat_bindot.py

@@ -281,9 +281,7 @@ def densitybin(
     if all(pd.isna(x)):
         return pd.DataFrame()
 
-    if weight is None:
-        weight = np.ones(len(x))
-    weight = np.asarray(weight)
+    weight = np.ones(len(x)) if weight is None else np.array(list(weight))
     weight[np.isnan(weight)] = 0
 
     if rangee is None:

tests/baseline_images/test_geom_bar_col_histogram/histogram_weights.png

@@ -99,3 +99,15 @@ def test_freedman_diaconis_bins():
     iqr1 = freedman_diaconis_bins(a1)
     iqr2 = freedman_diaconis_bins(a2)
     assert iqr1 == iqr2
+
+
+def test_histogram_weights():
+    data = pd.DataFrame(
+        {
+            "x": list(range(1, 6)),
+            "w": list(range(1, 6)),
+        }
+    )
+
+    p = ggplot(data, aes("x", weight="w")) + geom_histogram(bins=5)
+    assert p == "histogram_weights"