Wed Oct 23 17:39:12 PDT 2024

assets/slides/16.py

@@ -1,95 +1,44 @@
-from link import *
-
-
-def length(s):
-    """Return the number of elements in linked list s.
-
-    >>> length(Link(3, Link(4, Link(5))))
-    3
-    """
-    if s is Link.empty:
-        return 0
-    else:
-        return 1 + length(s.rest)
+t = [[1, 2], [3, 4]]
+t[0].append(t[1:2])
+
+def of(us):
+    def last(k):
+        "The last k items of us"
+        while k > 0:
+            result.append(us.pop())
+            k = k - 1
+        return result
+    return last
+
+def surround(n, f):
+    "n is the first and last item of f(2)"
+    result = [n]
+    result = f(2)
+    result[0] = [n]
+    return result.append(n)
+
+result = [1]
+surround(3, of([4, 5, 6]))
 
-def length_iter(s):
-    """Return the number of elements in linked list s.
+from link import *
 
-    >>> length_iter(Link(3, Link(4, Link(5))))
-    3
+def nested_link():
     """
-    k = 0
-    while s is not Link.empty:
-        s, k = s.rest, k + 1
-    return k
-
-def append(s, x):
-    """Append x to the end of non-empty s and return None.
-
-    >>> s = Link(3, Link(4, Link(5)))
-    >>> append(s, 6)
+    >>> s = Link(2, Link(3, Link(    4     , Link(5))))
+    >>> t = Link(2, Link(3, Link(  Link(4) , Link(5))))
     >>> print(s)
-    <3 4 5 6>
-    """
-    if s.rest: 
-        append(s.rest, x)
-    else:
-        s.rest = Link(x)
-
-def append_iter(s, x):
-    """Append x to the end of non-empty s and return None.
-
-    >>> s = Link(3, Link(4, Link(5)))
-    >>> append_iter(s, 6)
+    <2 3 4 5>
+    >>> print(t)
+    <2 3 <4> 5>
+    >>> s = Link(Link(8), Link(Link(4, Link(6, Link(Link(7)))), Link(5)))
     >>> print(s)
-    <3 4 5 6>
-    """
-    while s.rest:
-        s = s.rest
-    s.rest = Link(x)
-
-
-def pop(s, i):
-    """Remove and return element i from linked list s for positive i.
-
-    >>> t = Link(3, Link(4, Link(5, Link(6))))
-    >>> pop(t, 2)
-    5
-    >>> pop(t, 2)
-    6
-    >>> pop(t, 1)
-    4
-    >>> t
-    Link(3)
+    <<8> <4 6 <7>> 5>
+    >>> s.first.first
+    8
+    >>> s.rest.first.rest.rest.first
+    Link(7)
+    >>> s.rest.first.rest.rest.first.first
+    7
     """
-    assert i > 0 and i < length(s)
-    for x in range(i-1):
-        s = s.rest
-    result = s.rest.first
-    s.rest = s.rest.rest
-    return result
 
 
-def range_link(start, end):
-    """Return a Link containing consecutive integers from start to end.
-
-    >>> range_link(3, 6)
-    Link(3, Link(4, Link(5)))
-    """
-    if start >= end:
-        return Link.empty
-    else:
-        return Link(start, range_link(start + 1, end))
-
-def range_link_iter(start, end):
-    """Return a Link containing consecutive integers from start to end.
-
-    >>> range_link_iter(3, 6)
-    Link(3, Link(4, Link(5)))
-    """
-    s = Link.empty
-    k = end - 1
-    while k >= start:
-        s = Link(k, s)
-        k -= 1
-    return s

assets/slides/17.py

@@ -0,0 +1,162 @@
+from link import *
+
+def length(s):
+    """Return the number of elements in linked list s.
+
+    >>> length(Link(3, Link(4, Link(5))))
+    3
+    """
+    if s is Link.empty:
+        return 0
+    else:
+        return 1 + length(s.rest)
+
+def length_iter(s):
+    """Return the number of elements in linked list s.
+
+    >>> length_iter(Link(3, Link(4, Link(5))))
+    3
+    """
+    k = 0
+    while s is not Link.empty:
+        s, k = s.rest, k + 1
+    return k
+
+def append(s, x):
+    """Append x to the end of non-empty s and return None.
+
+    >>> s = Link(3, Link(4, Link(5)))
+    >>> append(s, 6)
+    >>> print(s)
+    <3 4 5 6>
+    """
+    if s.rest: 
+        append(s.rest, x)
+    else:
+        s.rest = Link(x)
+
+def append_iter(s, x):
+    """Append x to the end of non-empty s and return None.
+
+    >>> s = Link(3, Link(4, Link(5)))
+    >>> append_iter(s, 6)
+    >>> print(s)
+    <3 4 5 6>
+    """
+    while s.rest:
+        s = s.rest
+    s.rest = Link(x)
+
+
+def pop(s, i):
+    """Remove and return element i from linked list s for positive i.
+
+    >>> t = Link(3, Link(4, Link(5, Link(6))))
+    >>> pop(t, 2)
+    5
+    >>> pop(t, 2)
+    6
+    >>> pop(t, 1)
+    4
+    >>> t
+    Link(3)
+    """
+    assert i > 0 and i < length(s)
+    for x in range(i-1):
+        s = s.rest
+    result = s.rest.first
+    s.rest = s.rest.rest
+    return result
+
+
+def range_link(start, end):
+    """Return a Link containing consecutive integers from start to end.
+
+    >>> range_link(3, 6)
+    Link(3, Link(4, Link(5)))
+    """
+    if start >= end:
+        return Link.empty
+    else:
+        return Link(start, range_link(start + 1, end))
+
+def range_link_iter(start, end):
+    """Return a Link containing consecutive integers from start to end.
+
+    >>> range_link_iter(3, 6)
+    Link(3, Link(4, Link(5)))
+    """
+    s = Link.empty
+    k = end - 1
+    while k >= start:
+        s = Link(k, s)
+        k -= 1
+    return s
+
+# Iterators
+
+def iterator_demos():
+    """Using iterators
+
+    >>> s = [[1, 2], 3, 4, 5]
+    >>> next(s)
+    Traceback (most recent call last):
+        ...
+    TypeError: 'list' object is not an iterator
+    >>> t = iter(s)
+    >>> next(t)
+    [1, 2]
+    >>> next(t)
+    3
+    >>> u = iter(s)
+    >>> next(u)
+    [1, 2]
+    >>> list(t)
+    [4, 5]
+
+    >>> a = [1, 2, 3]
+    >>> b = [a, 4]
+    >>> c = iter(a)
+    >>> d = c
+    >>> print(next(c))
+    1
+    >>> print(next(d))
+    2
+    >>> b
+    [[1, 2, 3], 4]
+    """
+
+def double(x):
+    print('***', x, '=>', 2*x, '***')
+    return 2*x
+
+def built_in_demo():
+    """Using built-in sequence functions.
+
+    >>> bcd = ['b', 'c', 'd']
+    >>> [x.upper() for x in bcd]
+    ['B', 'C', 'D']
+    >>> caps = map(lambda x: x.upper(), bcd)
+    >>> next(caps)
+    'B'
+    >>> next(caps)
+    'C'
+    >>> s = range(3, 7)
+    >>> doubled = map(double, s)
+    >>> next(doubled)
+    *** 3 => 6 ***
+    6
+    >>> next(doubled)
+    *** 4 => 8 ***
+    8
+    >>> list(doubled)
+    *** 5 => 10 ***
+    *** 6 => 12 ***
+    [10, 12]
+    >>> all(map(double, range(-3, 3)))
+    *** -3 => -6 ***
+    *** -2 => -4 ***
+    *** -1 => -2 ***
+    *** 0 => 0 ***
+    False
+    """

index.html

@@ -160,7 +160,7 @@ <h2 class="frontpage-header">Announcements: Wednesday, October 23</h2>
   <ul>
     <li>Arrive by 8pm to find your seat; the exam will start at 8:10pm.</li>
     <li>Seat assignments will be emailed to you before the exam (probably Tuesday)</li>
-    <li>Complete the alteration request form (coming very soon) by Sunday, 10/27 at 11:59pm for any seating/timing requests (including DSP students).</li>
+    <li>Complete the <a href="https://forms.gle/T5swr13pQX1ZiD937">alteration request form</a> by Sunday, 10/27 at 11:59pm for any seating/timing requests (including DSP students).</li>
     <li>The exam covers material in the videos through Monday 10/21 (Linked Lists).</li>
     <li>You may bring up to 2 2-sided sheets of notes.</li>
     <li>The <a href="https://c88c.org/fa24/assets/pdfs/c88c-mt-study-guide.pdf">midterm study guide</a> will be printed for you and provided with your exam.</li>
@@ -1245,6 +1245,8 @@ <h2 class="frontpage-header">Calendar</h2>
 
 <ul class="list-inline">
   <li><a href="https://www.youtube.com/watch?v=On-kFyFp8HY&list=PL6BsET-8jgYW7stiut93PHxGP6_QgBzVQ&ab_channel=JohnDeNero" class="label label-outline" target="_blank">Videos</a></li>
+<li><a href="/fa24/assets/slides/17-Iterators_1pp.pdf" class="label label-outline">Slides (1pp)</a></li>
+<li><a href="/fa24/assets/slides/17.py" class="label label-outline">17.py</a></li>
 </ul>
 </td>
 <td>
@@ -1614,7 +1616,7 @@ <h3><a href="/articles/about">Policies</a></h3>
 
  });
 
- let build_time = new Date(1000 * 1729713393.664832);
+ let build_time = new Date(1000 * 1729730159.008139);
  </script>
  <script>
   $('.alwaystoggle').css('display', 'inline-block');