day19_reading_journal.ipynb

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    "# Day 19 Reading Journal\n",
    "\n",
    "This journal includes several required exercises, but it is meant to encourage active reading more generally.  You should use the journal to take detailed notes, catalog questions, and explore the content from Think Python deeply.\n",
    "\n",
    "Reading: Think Python **2** Chapter 19\n",
    "\n",
    "**Due: Thursday, April 7 at 12 noon**\n"
   ]
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    "## [Chapter 19](http://greenteapress.com/thinkpython2/html/thinkpython2020.html)\n",
    "\n",
    "This reading is \"the goodies\" - all the cool Python features that aren't strictly necessary but can make your code more concise, readable, and/or efficient.\n",
    "\n",
    "**Note:** This chapter is taken from the Think Python second edition, which is written for Python 3. There are [several differences](https://blog.appdynamics.com/devops/the-key-differences-between-python-2-and-python-3/) between Python 2 and 3, but the main one that comes up in this chapter is that '''print''' is a normal function (with parentheses) in Python 3 instead of a special statement. The rest of the concepts you read about in this chapter are also available in Python 2.7.\n",
    "\n",
    "You can read any of the sections you like, but we particularly recommend sections 2, 5, 9."
   ]
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    "is_question": true,
    "problem": "Exercise 19.1"
   },
   "source": [
    "### Exercise 1  \n",
    "\n",
    "Rewrite the following functions using list comprehensions."
   ]
  },
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   "execution_count": 1,
   "metadata": {
    "collapsed": false,
    "solution": "Exercise 19.1"
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   "source": [
    "def square(seq):\n",
    "    \"\"\"\n",
    "    Return a new list containing all the elements of 'seq'uence squared.\n",
    "    \n",
    "    >>> square([1, 2, 3])\n",
    "    [1, 4, 9]\n",
    "    >>> square([0, -5, 2.5])\n",
    "    [0, 25, 6.25]\n",
    "    >>> square([8, \"hello\", 10])\n",
    "    Traceback (most recent call last):\n",
    "      ...\n",
    "    TypeError: unsupported operand type(s) for ** or pow(): 'str' and 'int'\n",
    "    \"\"\"\n",
    "    return [s**2 for s in seq]\n",
    "\n",
    "def evens(seq):\n",
    "    \"\"\"\n",
    "    Return a new list containing only the elements of 'seq'uence that are even.\n",
    "    \n",
    "    >>> evens([1, 2, 3, 4])\n",
    "    [2, 4]\n",
    "    >>> evens(square(range(5)))\n",
    "    [0, 4, 16]\n",
    "    \"\"\"\n",
    "    return [s for s in seq if s % 2 == 0]\n",
    "\n",
    "import doctest\n",
    "doctest.testmod()\n",
    "        "
   ]
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   "metadata": {},
   "source": [
    "## [Exceptions](https://docs.python.org/2/tutorial/errors.html)\n",
    "\n",
    "Read about Exceptions in Python and how to handle them (through section 8.4).\n",
    "\n",
    "Advanced (optional): Check out [context managers](https://docs.python.org/2/reference/datamodel.html#context-managers) and the ['''with''' statement](https://www.python.org/dev/peps/pep-0343/)."
   ]
  },
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   "cell_type": "markdown",
   "metadata": {
    "is_question": true,
    "problem": "Exercise 19.2"
   },
   "source": [
    "### Exercise 2 \n",
    "\n",
    "Complete the following function using an exception handler. How else might you implement it?"
   ]
  },
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   "cell_type": "code",
   "execution_count": 4,
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    "collapsed": false,
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    "solution": "Exercise 19.2"
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   "outputs": [],
   "source": [
    "names = {\"Paul\": \"Ruvolo\", \"Oliver\": \"Steele\", \"Ben\": \"Hill\"}\n",
    "\n",
    "def formal_greeting(first_name, name_dict):\n",
    "    \"\"\"\n",
    "    Greet SoftDes professors by last name, and strangers with some skepticism.\n",
    "    \n",
    "    >>> formal_greeting(\"Oliver\", names)\n",
    "    Hello, Professor Steele!\n",
    "    >>> formal_greeting(\"Jasper\", names)\n",
    "    Howdy, stranger!\n",
    "    \"\"\"\n",
    "    try:\n",
    "        print \"Hello, Professor {}!\".format(name_dict[first_name])\n",
    "    except :\n",
    "        print \"Howdy, stranger!\"\n",
    "\n",
    "doctest.run_docstring_examples(formal_greeting, globals())    "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "is_poll": true,
    "is_question": true,
    "problem": "Time spent"
   },
   "source": [
    "## Quick poll\n",
    "About how long did you spend working on this Reading Journal?"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "poll_response": true,
    "solution": "Time spent"
   },
   "source": [
    "30 minutes"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "is_question": true,
    "problem": "Feedback"
   },
   "source": [
    "## Reading Journal feedback\n",
    "\n",
    "Have any comments on this Reading Journal? Feel free to leave them below and we'll read them when you submit your journal entry. This could include suggestions to improve the exercises, topics you'd like to see covered in class next time, or other feedback.\n",
    "\n",
    "If you have Python questions or run into problems while completing the reading, you should post them to Piazza instead so you can get a quick response before your journal is submitted."
   ]
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   "cell_type": "markdown",
   "metadata": {
    "feedback_response": true,
    "solution": "Feedback"
   },
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    " "
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