three method use dictionary

Author: m15kh

chapter7.py

@@ -0,0 +1,29 @@
+name_for_userid = {
+382: 'Alice',
+950: 'Bob',
+590: 'Dilbert',
+}
+
+
+#first method
+def greeting1(userid):
+    if userid in name_for_userid:
+        print('Hi %s!1' % name_for_userid[userid])
+    else:
+        print("hi there 1")
+greeting1(3820)
+
+# betteer method
+
+def greeting2(userid):
+    try:
+        print('Hi %s!2' % name_for_userid[userid])
+    except KeyError:
+        print("hello theree 2")
+greeting2(382)
+
+def greeting3(userid):
+    print('Hi %s! 3' % name_for_userid.get(userid, "there"))
+
+greeting3(38002)
+

itreator_generator.py

@@ -16,3 +16,12 @@ def negated(seq):
 
 chain3 = negated(squared(integers()))
 print(list(chain3))
+
+
+#short form above code
+# generator chain expressions
+
+integers = range(8)
+squared = (i * i for i in integers)
+negated = (-i for i in squared)
+print(list(negated))