All of HW for last three classes

Author: Dave Fugelso

Students/Dave Fugelso/Session 8/generator_solution.py

@@ -0,0 +1,104 @@
+def y_xrange(start, stop, step=1):
+    i = start
+    while i < stop:
+        yield i
+        i += step
+  
+
+
+def intsum():
+    '''
+    keep adding the next integer
+
+    0 + 1 + 2 + 3 + 4 + 5 + ...
+
+    so the sequence is:
+
+    0, 1, 3, 6, 10, 15 .....
+    '''
+    i = 0
+    sum = 0
+    
+    while True:
+        sum = i + sum
+        yield sum
+        i += 1
+
+
+def intsum2():
+    '''
+    test_generator has a intsum2... dunno why
+    '''
+    i = 0
+    sum = 0
+    
+    while True:
+        sum = i + sum
+        yield sum
+        i += 1
+
+def doubler():
+    '''
+    Doubler:
+    Each value is double the previous value:
+
+    1, 2, 4, 8, 16, 32,
+    '''
+    sum = 1
+    while True:
+        yield sum
+        sum += sum
+ 
+def fib():
+    '''
+    Fibonacci sequence:
+    The fibonacci sequence as a generator:
+
+    f(n) = f(n-1) + f(n-2)
+
+    1, 1, 2, 3, 5, 8, 13, 21, 34...
+    '''
+    yield 1
+    x = 0
+    y = 1
+    while True:
+        yield x+y
+        x, y = y, x+y
+
+    
+        
+
+        
+def isprime(n):
+    '''check if integer n is a prime'''
+    # make sure n is a positive integer
+    n = abs(int(n))
+    # 0 and 1 are not primes
+    if n < 2:
+        return False
+    # 2 is the only even prime number
+    if n == 2: 
+        return True
+    # all other even numbers are not primes
+    if not n & 1: 
+        return False
+    # range starts with 3 and only needs to go up the squareroot of n
+    # for all odd numbers
+    for x in range(3, int(n**0.5)+1, 2):
+        if n % x == 0:
+            return False
+    return True
+    
+def prime(): 
+    '''
+    Prime numbers:
+    Generate the prime numbers (numbers only divisible by them self and 1):
+
+    2, 3, 5, 7, 11, 13, 17, 19, 23...
+    '''
+    i = 2
+    while True:
+        while not isprime (i):
+            i += 1
+        yield i
+        i += 1

Students/Dave Fugelso/Session 8/test_generator.py

@@ -0,0 +1,78 @@
+"""
+test_generator.py
+
+tests the solution to the generator lab
+
+can be run with py.test or nosetests
+"""
+
+import generator_solution as gen
+
+
+def test_intsum():
+
+    g = gen.intsum()
+
+    assert g.next() == 0
+    assert g.next() == 1
+    assert g.next() == 3
+    assert g.next() == 6
+    assert g.next() == 10
+    assert g.next() == 15
+
+
+def test_intsum2():
+
+    g = gen.intsum2()
+
+    assert g.next() == 0
+    assert g.next() == 1
+    assert g.next() == 3
+    assert g.next() == 6
+    assert g.next() == 10
+    assert g.next() == 15
+
+
+def test_doubler():
+
+    g = gen.doubler()
+
+    assert g.next() == 1
+    assert g.next() == 2
+    assert g.next() == 4
+    assert g.next() == 8
+    assert g.next() == 16
+    assert g.next() == 32
+
+    for i in range(10):
+        j = g.next()
+
+    assert j == 2**15
+
+
+def test_fib():
+    g = gen.fib()
+
+    assert g.next() == 1
+    assert g.next() == 1
+    assert g.next() == 2
+    assert g.next() == 3
+    assert g.next() == 5
+    assert g.next() == 8
+    assert g.next() == 13
+    assert g.next() == 21
+
+
+def test_prime():
+    g = gen.prime()
+
+    assert g.next() == 2
+    assert g.next() == 3
+    assert g.next() == 5
+    assert g.next() == 7
+    assert g.next() == 11
+    assert g.next() == 13
+    assert g.next() == 17
+    assert g.next() == 19
+    assert g.next() == 23
+

Students/Dave Fugelso/Session 9/p_wrapper.py

@@ -19,10 +19,14 @@ def string_return (string):
 class tag_wrapper (object):
 
     def __init__(self, tag):
+        #print "Inside __init__()"
         self.tag = tag
 
-    @p_wrapper
     def __call__(self, string):
-        def string_return (string):
-            string = '<'+self.tag+'> '+string+' </'+self.tag+'p>'
-        return string_return
+        #print "Inside __call__()"
+        def tagged_line (string):
+           # print 'decorator'
+           # print '<'+self.tag+'> '+string+' </'+self.tag+'>'
+            return '<'+self.tag+'> '+string+' </'+self.tag+'>'
+        return tagged_line
+        

Students/Dave Fugelso/Session 9/test_p_wrapper.py

@@ -30,6 +30,3 @@ def return_a_string(string):
 
     assert return_a_string("this is a string") == "<div> this is a string </div>"
 
-test_p_wrapper()
-test_tag_wrapper()
-test_tag_wrapper2()

Students/Dave Fugelso/Session 9/test_timer.py

@@ -0,0 +1,15 @@
+'''
+Test timer context manager.
+'''
+
+from timer import * 
+
+def test_timer():
+    print 'test'
+    with Timer() as t:
+        for i in range(100000):
+            i = i ** 20
+    print t.elapsed_time()
+    assert t.elapsed_time() > 0
+    
+test_timer()

Students/Dave Fugelso/Session 9/timer.py

@@ -0,0 +1,22 @@
+import time
+
+class Timer (object):
+    '''
+    Context manager that prints elapsed time on exit.
+    '''
+    def __init__(self):
+        print 'init'
+        pass
+
+
+    def __enter__(self):
+        print 'enter'
+        self.start = time.time()
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        print 'Exit'
+        self.end = time.time()
+        
+    def elapsed_time (self):
+        return self.end - self.start