diff --git a/gallery_dl/extractor/common.py b/gallery_dl/extractor/common.py
index 9cf07335..03956654 100644
--- a/gallery_dl/extractor/common.py
+++ b/gallery_dl/extractor/common.py
@@ -731,9 +731,8 @@ class GalleryExtractor(Extractor):
     def __init__(self, match, url=None):
         Extractor.__init__(self, match)
 
-        if url is None:
-            path = self.groups[0]
-            self.page_url = self.root + path if path[0] == "/" else None
+        if url is None and (path := self.groups[0]) and path[0] == "/":
+            self.page_url = f"{self.root}{path}"
         else:
             self.page_url = url
 
@@ -829,9 +828,8 @@ class MangaExtractor(Extractor):
     def __init__(self, match, url=None):
         Extractor.__init__(self, match)
 
-        if url is None:
-            path = self.groups[0]
-            self.page_url = self.root + path if path[0] == "/" else None
+        if url is None and (path := self.groups[0]) and path[0] == "/":
+            self.page_url = f"{self.root}{path}"
         else:
             self.page_url = url