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 "cells": [
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Denison CS181/DA210 Homework\n",
    "\n",
    "Before you turn this problem in, make sure everything runs as expected. This is a combination of **restarting the kernel** and then **running all cells** (in the menubar, select Kernel$\\rightarrow$Restart And Run All).\n",
    "\n",
    "Make sure you fill in any place that says `YOUR CODE HERE` or \"YOUR ANSWER HERE\"."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "---"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import json\n",
    "import os\n",
    "import os.path\n",
    "import io\n",
    "import sys\n",
    "from contextlib import redirect_stdout\n",
    "\n",
    "datadir = \"publicdata\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Q1:** In the data directory is a file named `fib.json` containing a JSON-encoded list of numbers from the Fibonacci sequence.  Write a function\n",
    "\n",
    "    readJSONlist(path)\n",
    "\n",
    "that reads and returns a list from `path`, **assuming a JSON-encoded text file**.  If `path` does not exist, or if the result is a data structure other than a list, return the empty list. (Hint: the Python function `isinstance()` can be helpful to verify the type of a data structure.)\n",
    "\n",
    "Then invoke the function on `fib.json` in `datadir` and assign the result to `result`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "3fca93a65c6f2a016ab519bfee14ef77",
     "grade": false,
     "grade_id": "cell-d2bae836fbc119c2",
     "locked": false,
     "schema_version": 3,
     "solution": true,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# Solution cell\n",
    "\n",
    "# YOUR CODE HERE\n",
    "raise NotImplementedError()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "editable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "f71fb6b464182fce4255145e2a236b5f",
     "grade": true,
     "grade_id": "cell-82c0e42c81213cef",
     "locked": true,
     "points": 3,
     "schema_version": 3,
     "solution": false,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# Testing cell\n",
    "\n",
    "assert result[-1] == 89\n",
    "assert len(result) == 12\n",
    "\n",
    "result2 = readJSONlist(\"./foobar.json\")\n",
    "assert result2 == []\n",
    "\n",
    "result3 = readJSONlist(os.path.join(datadir, \"config.json\"))\n",
    "assert result3 == []"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Q2:** Write a function\n",
    "\n",
    "    writeSquares(N, filepath)\n",
    "\n",
    "that creates a list of the squares of integers from 1 to `N` and then writes them out as a JSON-encoded text file to the file location given by `filepath`.  If N is less than or equal to 0, no file should be created.  This function returns no value."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "3fd16cfa9b93fd5243c867cd8a63f29e",
     "grade": false,
     "grade_id": "cell-469c714260019773",
     "locked": false,
     "schema_version": 3,
     "solution": true,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# Solution cell\n",
    "\n",
    "# YOUR CODE HERE\n",
    "raise NotImplementedError()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "editable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "672f8af0e387c045094b3d43c2968f2d",
     "grade": true,
     "grade_id": "cell-e64a97ee03c45a63",
     "locked": true,
     "points": 3,
     "schema_version": 3,
     "solution": false,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# Testing cell\n",
    "\n",
    "filepath = \"./squares.json\"\n",
    "writeSquares(5, filepath)\n",
    "result = json.load(open(filepath, 'r'))\n",
    "assert result == [1, 4, 9, 16, 25]\n",
    "writeSquares(1, filepath)\n",
    "result = json.load(open(filepath, 'r'))\n",
    "assert result == [1]\n",
    "os.remove(filepath)\n",
    "writeSquares(0, filepath)\n",
    "assert not os.path.isfile(filepath)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Q3:** In the data directory is a file named `baby_2015_female_namecount.txt` with a line for each of the top female baby names of 2015.  Each line contains tab-separated values for the name and the count of US Social Security applications for that name.  Start by writing a function\n",
    "\n",
    "    readNameCount(path)\n",
    "\n",
    "that reads a file formatted this way, given by `path` and returns a tuple of two lists, the first being the names and the second being the counts.  The function should behave properly regardless of how many name-count lines are in the file.  If the specified path does not exist, your function should return `None`.  Make sure your count values are integers.\n",
    "\n",
    "Then write code that *uses* your function to obtain the lists and **writes the result** to a **JSON-encoded** text file in the current directory named `namecount.json`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "7c0c9e4ae02d2722b1c8db8dd4c48c9f",
     "grade": false,
     "grade_id": "cell-00f558d6134a208b",
     "locked": false,
     "schema_version": 3,
     "solution": true,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# Solution cell\n",
    "\n",
    "# YOUR CODE HERE\n",
    "raise NotImplementedError()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "editable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "475f4c55e1eda7d3dd2e50af27f31ba4",
     "grade": true,
     "grade_id": "cell-8d778e7c955efac5",
     "locked": true,
     "points": 3,
     "schema_version": 3,
     "solution": false,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# Testing cell\n",
    "\n",
    "assert readNameCount(\"./foo\") == None\n",
    "result = readNameCount(os.path.join(datadir, \"baby_2015_female_namecount.txt\"))\n",
    "assert len(result) == 2\n",
    "assert len(result[0]) == 10\n",
    "assert len(result[1]) == 10\n",
    "jsonpath = os.path.join(\".\", \"namecount.json\")\n",
    "assert os.path.isfile(jsonpath)\n",
    "with open(jsonpath, 'r') as f:\n",
    "    result2 = json.load(f)\n",
    "assert len(result2) == 2\n",
    "assert len(result2[0]) == 10\n",
    "assert len(result2[1]) == 10"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**Q4:** Consider the table of data:\n",
    "\n",
    "subject | name | department\n",
    "---------|-----|--------------\n",
    "CS | Computer Science | MATH\n",
    "MATH | Mathematics | MATH\n",
    "ENGL | English Literature | ENGL\n",
    "\n",
    "This could be represented in a Python program as a *dictionary* mapping from a key, `\"subjects\"`, to a *list* of dictionaries, one per subject.  These inner dictionaries map from `\"subject\"`, `\"name\"`, and `\"department\"` to the respective value for the row.  Be careful and follow the above specification **exactly**.\n",
    "\n",
    "Write Python code to construct the above representation as a Python in-memory data structure called `ds`, and then have your code **encode the data structure** into a JSON-formatted string called `s`.  Print the string.  Then take `ds` and encode as a JSON-formatted string, but include `indent=2` as an argument in the conversion, and assign to `s2` and print it."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "364d4fa4d63009ff7faa54409fb15953",
     "grade": false,
     "grade_id": "cell-0abd378083a7bdd9",
     "locked": false,
     "schema_version": 3,
     "solution": true,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# YOUR CODE HERE\n",
    "raise NotImplementedError()\n",
    "print(s)\n",
    "print(s2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "deletable": false,
    "editable": false,
    "nbgrader": {
     "cell_type": "code",
     "checksum": "38d8ce0d5ab6a78e0a425875000451ee",
     "grade": true,
     "grade_id": "cell-765331274d04ea6d",
     "locked": true,
     "points": 3,
     "schema_version": 3,
     "solution": false,
     "task": false
    }
   },
   "outputs": [],
   "source": [
    "# Testing Cell\n",
    "\n",
    "f = io.StringIO()\n",
    "with redirect_stdout(f):\n",
    "    print(s)\n",
    "    \n",
    "assert f.getvalue() == '{\"subjects\": [{\"subject\": \"CS\", \"name\": \"Computer Science\", \"department\": \"MATH\"}, {\"subject\": \"MATH\", \"name\": \"Mathematics\", \"department\": \"MATH\"}, {\"subject\": \"ENGL\", \"name\": \"English Literature\", \"department\": \"ENGL\"}]}\\n'\n",
    "\n",
    "f2 = io.StringIO()\n",
    "with redirect_stdout(f2):\n",
    "    print(s2)\n",
    "\n",
    "assert f2.getvalue() == '{\\n  \"subjects\": [\\n    {\\n      \"subject\": \"CS\",\\n      \"name\": \"Computer Science\",\\n      \"department\": \"MATH\"\\n    },\\n    {\\n      \"subject\": \"MATH\",\\n      \"name\": \"Mathematics\",\\n      \"department\": \"MATH\"\\n    },\\n    {\\n      \"subject\": \"ENGL\",\\n      \"name\": \"English Literature\",\\n      \"department\": \"ENGL\"\\n    }\\n  ]\\n}\\n'"
   ]
  }
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