add previews to obs columns too

app.py

@@ -60,11 +60,11 @@ def _pick_layer(adata, layer_name):
         X = X.toarray()
     return X
 
-# helper to summarize .var columns
-def _summarize_var_columns(adata_var_df, preview_max=VAR_PREVIEW_MAX):
+# helper to summarize DataFrame column choices
+def _summarize_columns(df, preview_max=VAR_PREVIEW_MAX):
     choices = []
-    for col in adata_var_df.columns:
-        s = adata_var_df[col]
+    for col in df.columns:
+        s = df[col]
         dtype = str(s.dtype)
         ex = pd.Series(s.astype(object)).dropna().astype(str).head(preview_max).tolist()
         preview = ", ".join(ex) if ex else "—"
@@ -121,7 +121,7 @@ def ensure_dropdowns(fileobj):
         adata = sc.read_h5ad(fileobj.name, backed="r")
         adata.var = adata.var.reset_index(drop=False, names="index")
         layers = list(adata.layers.keys())
-        var_choices = _summarize_var_columns(adata.var)
+        var_choices = _summarize_columns(adata.var)
         del adata
         gc.collect()
         default_var = var_choices[0][1] if var_choices else None
@@ -445,8 +445,8 @@ def _embed(adata_bytes, layer_name, feature_col, use_symbols, progress):
 
     # hand back small metadata for UI refresh
     layers = list(adata.layers.keys())
-    var_cols = list(adata.var.columns)
-    obs_cols = list(adata.obs.columns)
+    var_choices = _summarize_columns(adata.var)
+    obs_choices = _summarize_columns(adata.obs)
 
     # serialize AnnData back to bytes for CPU side
     with tempfile.TemporaryDirectory() as td2:
@@ -461,7 +461,7 @@ def _embed(adata_bytes, layer_name, feature_col, use_symbols, progress):
     gc.collect()
 
     # return embeddings and metadata
-    return cell_array, layers, var_cols, obs_cols, adata_persisted
+    return cell_array, layers, var_choices, obs_choices, adata_persisted
 
 # processing pipeline given user inputs
 def run_pipeline(fileobj, layer_choice, var_choice, use_symbols, progress=gr.Progress(track_tqdm=False)):
@@ -478,7 +478,7 @@ def run_pipeline(fileobj, layer_choice, var_choice, use_symbols, progress=gr.Pro
         adata_bytes = f.read()
 
     # compute embeddings on GPU
-    E, layers, var_cols, obs_cols, adata_with_emb_bytes = _embed(
+    E, layers, var_choices, obs_choices, adata_with_emb_bytes = _embed(
         adata_bytes=adata_bytes,
         layer_name=(None if layer_choice in [None, "", "<use .X>"] else layer_choice),
         feature_col=(None if var_choice in [None, ""] else var_choice),
@@ -512,13 +512,13 @@ def run_pipeline(fileobj, layer_choice, var_choice, use_symbols, progress=gr.Pro
     plt.close(fig)
 
     # enable coloring dropdown
-    update_obs_dd = gr.Dropdown(choices=[OBS_NONE_OPTION] + obs_cols, value=OBS_NONE_OPTION, interactive=True)
+    update_obs_dd = gr.Dropdown(choices=[OBS_NONE_OPTION] + obs_choices, value=OBS_NONE_OPTION, interactive=True)
 
     # save other outputs and return paths
     progress(0.95, desc="saving outputs")
     parquet_path, h5ad_path = _save_outputs(adata, E)
     progress(1.00, desc="finished!")
-    return str(umap_png.resolve()), str(parquet_path.resolve()), str(h5ad_path.resolve()), ["<use .X>"] + layers, var_cols, update_obs_dd, coords, str(h5ad_path.resolve())
+    return str(umap_png.resolve()), str(parquet_path.resolve()), str(h5ad_path.resolve()), ["<use .X>"] + layers, var_choices, update_obs_dd, coords, str(h5ad_path.resolve())
 
 # specify app layout
 css = """