Added a clarifier for boolean and/or combinations.

lesson4exercises.ipynb

@@ -104,6 +104,65 @@
    "outputs": [],
    "source": []
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Here's some example code for comparing multiple conditions at a time.  You'll use it in the next problem.  Here, just focus on understanding what it does.  You can use the word \"and\" between two conditions.  The whole thing will be true only if both of the sub-parts are true.  You can use the word \"or\" between two conditions.  The whole thing will be true if either one sub-part or the other is true (as well as if both are true).  \n",
+    "\n",
+    "AND means that every part must be true for the if statement to be true.  OR means that at least one part must be true for the whole thing to be true."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "It's a beautiful sunny day.\n"
+     ]
+    }
+   ],
+   "source": [
+    "weather=\"clear\"\n",
+    "time=\"daytime\"\n",
+    "if (weather==\"clear\" and time==\"daytime\"):\n",
+    "    print(\"It's a beautiful sunny day.\")\n",
+    "elif (weather==\"clear\" and time==\"night\"):\n",
+    "    print(\"It's a good time to watch the stars.\")\n",
+    "else:\n",
+    "    print(\"I didn't expect that weather.\")\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "First condition\n"
+     ]
+    }
+   ],
+   "source": [
+    "num=12\n",
+    "if (num > 20 or num < 15):\n",
+    "    print(\"First condition\")\n",
+    "if (num < 0):\n",
+    "    print(\"Negative number\")\n",
+    "    "
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -192,21 +251,21 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 2",
    "language": "python",
-   "name": "python3"
+   "name": "python2"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
-    "version": 3
+    "version": 2
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.3.5"
+   "pygments_lexer": "ipython2",
+   "version": "2.7.10"
   }
  },
  "nbformat": 4,