Fix collate script.

Author: eswan18

uc_python/collate.py

@@ -1,12 +1,21 @@
+import shutil
 from pathlib import Path
 
 folder = Path("repos")
-site = Path("site")
+site = Path("site").absolute()
 site.mkdir(exist_ok=True)
+subfolders = [f for f in site.glob("*") if f.is_dir()]
+for s in subfolders:
+    print(f"deleting {s}")
+    shutil.rmtree(s)
 
 # Build an index as we go
 index = site / "index.html"
 index.write_text("<h1>UC Python Slides</h1>")
 for repo in folder.glob("*"):
-    (repo / "slides").rename(site / repo.name)
-    index.write_text(f'<a href="/{repo.name}">{repo.name}</a>')
+    slides_dir = (repo / "slides")
+    if not slides_dir.exists():
+        print(f"no slides in {slides_dir}, skipping")
+        continue
+    slides_dir.rename(site / repo.name)
+    index.write_text(f'<a href="/{repo.name}">{repo.name}</a>\n')