in-text question for week 5 added

week_5/in-text/intSet.py

@@ -0,0 +1,51 @@
+# Exercise: int set
+
+# Your task is to define the following two methods for the intSet class:
+#   1. Define an intersect method that returns a new intSet containing elements that appear in both sets.
+#      In other words, s1.intersect(s2) would return a new intSet of integers that appear in both s1 and s2.
+
+#   2. Add the appropriate method(s) so that len(s) returns the number of elements in s.
+
+class intSet(object):
+    """An intSet is a set of integers
+    The value is represented by a list of ints, self.vals.
+    Each int in the set occurs in self.vals exactly once."""
+
+    def __init__(self):
+        """Create an empty set of integers"""
+        self.vals = []
+
+    def insert(self, e):
+        """Assumes e is an integer and inserts e into self"""
+        if not e in self.vals:
+            self.vals.append(e)
+
+    def member(self, e):
+        """Assumes e is an integer
+           Returns True if e is in self, and False otherwise"""
+        return e in self.vals
+
+    def remove(self, e):
+        """Assumes e is an integer and removes e from self
+           Raises ValueError if e is not in self"""
+        try:
+            self.vals.remove(e)
+        except:
+            raise ValueError(str(e) + ' not found')
+
+    def __str__(self):
+        """Returns a string representation of self"""
+        self.vals.sort()
+        return '{' + ','.join([str(e) for e in self.vals]) + '}'
+
+    def intersect(self, other):
+        """Returns intersection of both sets"""
+        commonList = intSet()
+        for element in self.vals:
+            if element in other.vals:
+                commonList.insert(element)
+        return commonList
+
+    def __len__(self):
+        return len(self.vals)
+