add yield sample

Author: michaelliao

py3/advance/do_yield.py

@@ -0,0 +1,31 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+import random, math
+
+def rnd(count):
+    while count > 0:
+        count = count - 1
+        r = random.randint(0, 100)
+        print('-- random number --')
+        # 返回随机数r:
+        yield r
+        # 代理返回tri(r)的yield，可能有很多次:
+        ok = yield from tri(r)
+        # 相当于:
+        # for x in tri(r):
+        #     yield x
+        print('-- %s --' % ok)
+    return 'done'
+
+def tri(r):
+    yield r * r
+    yield r * r * r
+    # 相当于: raise StopIteration('ok')
+    return 'ok'
+
+def main():
+    for x in rnd(3):
+        print(x)
+
+main()