add contextlib samples

michaelliao · michaelliao · commit 88abcd873347 · 2015-04-04T19:35:49.000+08:00
diff --git a/py3/context/do_closing.py b/py3/context/do_closing.py
@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from contextlib import contextmanager
+
+@contextmanager
+def closing(fname):
+    f = None
+    try:
+        f = open(fname, 'r')
+        yield f
+    finally:
+        if f:
+            f.close()
+
+with closing('test.txt') as f:
+    print(f.read())
diff --git a/py3/context/do_suppress.py b/py3/context/do_suppress.py
@@ -0,0 +1,11 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+import os
+
+from contextlib import suppress
+
+with suppress(FileNotFoundError):
+    os.remove('tempfile.1')
+    os.remove('tempfile.2')
+    os.remove('tempfile.3')
diff --git a/py3/context/do_with.py b/py3/context/do_with.py
@@ -0,0 +1,14 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+from contextlib import contextmanager
+
+@contextmanager
+def log(name):
+    print('[%s] start...' % name)
+    yield
+    print('[%s] end.' % name)
+
+with log('DEBUG'):
+    print('Hello, world!')
+    print('Hello, Python!')
