secret-santa.ipynb

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    "## Secret Santa drawing (or, TDD to the maxx)\n",
    "\n",
    "Like test-driven development? \n",
    "\n",
    "How about just having a test and the programming is just random until it passes?  \n",
    "\n",
    "Here's the set-up. We have a family Christmas drawing (for the adults, kids are no-limit gift recipients!) that involves four couples. There are four conditions that the drawing algorithm needs to satisfy: \n",
    "\n",
    "1. Everyone draws someone (exactly one person).\n",
    "1. Everyone gets drawn (exactly once).\n",
    "1. No one draws her or himself.\n",
    "1. No one draws his or her spouse. \n",
    "\n",
    "TBH I set up a grand scheme of randomizing names and assigning them and checking them one at a time (based on an analogy to an in-person draw) but that was overly fussy, so we're just going to set up a test for our four conditions, shuffle the list of names and see if the shuffled list zipped to the original list fails the test. "
   ]
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   "source": [
    "### Let's make our people into variables. "
   ]
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    "a = ('my mom', 'Mom', '[email protected]') \n",
    "            #'my mom', 'my dad', and 'me' (below)\n",
    "            #make sense in the syntax of the email template \n",
    "b = ('my dad', 'Dad', '[email protected]')\n",
    "c = ('Alice', 'Alice', '[email protected]')\n",
    "d = ('Bob', 'Bob', '[email protected]')\n",
    "e = ('Carol', 'Carol', '[email protected]')\n",
    "f = ('Dan', 'Dan', '[email protected]')\n",
    "g = ('Frank', 'Frank', '[email protected]')\n",
    "h = ('me', 'Tim', '[email protected]') \n",
    "            #I send this from an email I don't usually use to my regular account.\n",
    "\n",
    "names = [a, b, c, d, e, f, g, h]"
   ]
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   "source": [
    "And we'll define the 'ineligible receivers' for each person, too. In one version of this, I defined a list of lists: \n",
    "`couples = ((a, b), (c,d), (e,f), (g,h))`\n",
    "which made this part of the thing simple but made the checking part a bit more complicated. We're going to set this up to be a bit simpler down the road by making it a dictionary:"
   ]
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    "bad_recips = {\n",
    "    a : b,\n",
    "    b : a,\n",
    "    c : d,\n",
    "    d : c,\n",
    "    e : f, \n",
    "    f : e,\n",
    "    g : h, \n",
    "    h : g\n",
    "}"
   ]
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  {
   "cell_type": "code",
   "execution_count": 4,
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   "source": [
    "from random import shuffle"
   ]
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   "source": [
    "I'm going to forego writing a test for conditions 1 and 2 b/c I'm just going to shuffle the list, zip it to the original list, and then test conditions 3 and 4. But let's go to those tests."
   ]
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    "# No one draws her or himself.\n",
    "\n",
    "def check_self(draw):\n",
    "    for pair in draw:\n",
    "        if pair[0] == pair [1]:\n",
    "            return False\n",
    "    return True\n",
    "        \n",
    "\n",
    "# No one draws his or her spouse.\n",
    "def check_spouse(draw):\n",
    "    for pair in draw:\n",
    "        if bad_recips[pair[0]] == pair [1]:\n",
    "            return False\n",
    "    return True\n"
   ]
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   "cell_type": "markdown",
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   "source": [
    "Now, we'll get to doing a drawing, checking it, and returning it if it satisfies the conditions."
   ]
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   "cell_type": "code",
   "execution_count": 6,
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   "source": [
    "def draw(nameslist):\n",
    "    drawlist = nameslist.copy()\n",
    "    shuffle(drawlist)\n",
    "    return list(zip(nameslist, drawlist))"
   ]
  },
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   "cell_type": "code",
   "execution_count": 14,
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   "source": [
    "def run(nameslist):\n",
    "    candidate = draw(nameslist)\n",
    "    while not check_self(candidate) or not check_spouse(candidate):\n",
    "        candidate = draw(nameslist)\n",
    "    return candidate"
   ]
  },
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   "cell_type": "code",
   "execution_count": 18,
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   "source": [
    "pairs = run(names)\n"
   ]
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   "cell_type": "code",
   "execution_count": 19,
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   "source": [
    "import smtplib\n",
    "from email.mime.multipart import MIMEMultipart\n",
    "from email.mime.text import MIMEText\n",
    "\n",
    "for pair in pairs:\n",
    "    msg = MIMEMultipart()\n",
    "    msg['From'] = '[email protected]'\n",
    "    msg['To'] = toaddrs\n",
    "    msg['subject'] = 'Secret Santa Drawing!'\n",
    "    body = ''' Hi, ''' + pair[0][1] + ''' \n",
    "    Here's this year's Christmas drawing (at, um, last)!\n",
    "    \n",
    "    You're going to be giving a gift to:\n",
    "    ''' + pair[1][0] + '''\n",
    "    \n",
    "    \n",
    "    It's a bit late, but you've got 23 days.\n",
    "    \n",
    "    Thanks! and love to all, \n",
    "    Tim\n",
    "    '''\n",
    "    \n",
    "    msg.attach(MIMEText(body, 'plain'))\n",
    "\n",
    "\n",
    "    # Credentials (if needed)\n",
    "    username = '[email protected]'\n",
    "    password = 'PASSWORD' #Note that if you have 2FA enabled in gmail, you can create an app-specific password for your script.\n",
    "\n",
    "    # The actual mail send\n",
    "    server = smtplib.SMTP('smtp.gmail.com:587')\n",
    "    server.starttls()\n",
    "    server.login(username,password)\n",
    "    server.sendmail(fromaddr, toaddrs, msg.as_string())\n",
    "    server.quit()"
   ]
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   "cell_type": "code",
   "execution_count": null,
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