Extract path calculation for paths

1 files changed, 2 insertions, 3 deletions

diff --git a/setuptools/command/install_lib.py b/setuptools/command/install_lib.py
index 88b35972..92490b6e 100644
--- a/setuptools/command/install_lib.py
+++ b/setuptools/command/install_lib.py
@@ -17,12 +17,11 @@ class install_lib(orig.install_lib):
         excluded for single_version_externally_managed installations.
         """
         exclude = set()
+        pkg_path = lambda pkg: os.path.join(self.install_dir, *pkg.split('.'))
         for ns_pkg in self._get_SVEM_NSPs():
             for pkg in self._all_packages(ns_pkg):
-                parts = pkg.split('.')
-                pkgdir = os.path.join(self.install_dir, *parts)
                 for f in self._gen_exclude_names():
-                    exclude.add(os.path.join(pkgdir, f))
+                    exclude.add(os.path.join(pkg_path(pkg), f))
         return exclude
 
     @staticmethod