don't uninstall more packages

Pipfile

@@ -1,3 +1,6 @@
+[dev-packages]
+pytest = "*"
+
 [packages]
 click = "*"
 crayons = "*"
@@ -7,6 +10,3 @@ requests = "*"
 requirements-parser = "*"
 parse = "*"
 "backports.shutil_get_terminal_size" = "*"
-
-[dev-packages]
-pytest = "*"

pipenv/cli.py

@@ -385,11 +385,10 @@ def do_purge(bare=False, downloads=False, allow_global=False):
     installed = freeze.split()
 
     # Remove setuptools and friends from installed, if present.
-    for package_name in ['setuptools', 'pip', 'wheel', 'six']:
-        try:
-            installed.remove(package_name)
-        except ValueError:
-            pass
+    for package_name in ['setuptools', 'pip', 'wheel', 'six', 'packaging', 'pyparsing', 'appdirs']:
+        for i, package in enumerate(installed):
+            if package.startswith(package_name):
+                del installed[i]
 
     if not bare:
         click.echo('Found {0} installed package(s), purging...'.format(len(installed)))