Merge branch 'master' of github.com:michaelliao/learn-python3

Author: michaelliao

samples/advance/do_generator.py

@@ -23,18 +23,9 @@ def fib(max):
 g = fib(5)
 while 1:
     try:
-        x = g.send(None)
+        x = next(g)
         print('g:', x)
     except StopIteration as e:
         print('Generator return value:', e.value)
         break
 
-# call generator using iter:
-i = iter(fib(5))
-while 1:
-    try:
-        r = next(i)
-        print('i:', r)
-    except StopIteration as e:
-        print('Generator return value:', e.value)
-        break

samples/advance/do_iter.py

@@ -1,16 +1,41 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-from collections import Iterable
-print('iterable? [1, 2, 3]:', isinstance([1, 2, 3], Iterable))
-print('iterable? \'abc\':', isinstance('abc', Iterable))
-print('iterable? 123:', isinstance(123, Iterable))
+from collections import Iterable, Iterator
+
+def g():
+    yield 1
+    yield 2
+    yield 3
+
+print('Iterable? [1, 2, 3]:', isinstance([1, 2, 3], Iterable))
+print('Iterable? \'abc\':', isinstance('abc', Iterable))
+print('Iterable? 123:', isinstance(123, Iterable))
+print('Iterable? g():', isinstance(g(), Iterable))
+
+print('Iterator? [1, 2, 3]:', isinstance([1, 2, 3], Iterator))
+print('Iterator? iter([1, 2, 3]):', isinstance(iter([1, 2, 3]), Iterator))
+print('Iterator? \'abc\':', isinstance('abc', Iterator))
+print('Iterator? 123:', isinstance(123, Iterator))
+print('Iterator? g():', isinstance(g(), Iterator))
 
 # iter list:
-print('iter [1, 2, 3, 4, 5]')
+print('for x in [1, 2, 3, 4, 5]:')
 for x in [1, 2, 3, 4, 5]:
     print(x)
 
+print('for x in iter([1, 2, 3, 4, 5]):')
+for x in iter([1, 2, 3, 4, 5]):
+    print(x)
+
+print('next():')
+it = iter([1, 2, 3, 4, 5])
+print(next(it))
+print(next(it))
+print(next(it))
+print(next(it))
+print(next(it))
+
 d = {'a': 1, 'b': 2, 'c': 3}
 
 # iter each key:

samples/functional/do_reduce.py

@@ -23,3 +23,39 @@ def str2int(s):
 print(str2int('0'))
 print(str2int('12300'))
 print(str2int('0012345'))
+
+CHAR_TO_FLOAT = {
+    '0': 0,
+    '1': 1,
+    '2': 2,
+    '3': 3,
+    '4': 4,
+    '5': 5,
+    '6': 6,
+    '7': 7,
+    '8': 8,
+    '9': 9,
+    '.': -1
+}
+
+def str2float(s):
+    nums = map(lambda ch: CHAR_TO_FLOAT[ch], s)
+    point = -1
+    def to_float(f, n):
+        nonlocal point
+        if n == -1:
+            point = 0
+            return f
+        if point == -1:
+            return f * 10 + n
+        else:
+            point = point + 1
+            return f + n / pow(10, point)
+    return reduce(to_float, nums, 0.0)
+
+print(str2float('0'))
+print(str2float('123.456'))
+print(str2float('123.45600'))
+print(str2float('0.1234'))
+print(str2float('.1234'))
+print(str2float('120.0034'))

samples/functional/do_sorted.py

@@ -8,16 +8,8 @@
 print(sorted(L))
 print(sorted(L, key=str.lower))
 
-students = [
-    ('Adam', 90),
-    ('Tim', 60),
-    ('Lisa', 80),
-    ('Bart', 60)
-]
+students = [('Bob', 75), ('Adam', 92), ('Bart', 66), ('Lisa', 88)]
 
-print(sorted(students, key=itemgetter(1)))
-
-def student_to_key(t):
-    return '%+02d%s' % (100-t[1], t[0])
-
-print(sorted(students, key=student_to_key))
+print(sorted(students, key=itemgetter(0)))
+print(sorted(students, key=lambda t: t[1]))
+print(sorted(students, key=itemgetter(1), reverse=True))

samples/module/hello.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+' a test module '
+
+__author__ = 'Michael Liao'
+
+import sys
+
+def test():
+    args = sys.argv
+    if len(args)==1:
+            print('Hello, world!')
+    elif len(args)==2:
+        print('Hello, %s!' % args[1])
+    else:
+        print('Too many arguments!')
+
+if __name__=='__main__':
+    test()
+