Assignment2.ipynb

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    "# %load assignment2.py"
   ]
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      "verbing\n",
      " OK  got: 'hailing' expected: 'hailing'\n",
      " OK  got: 'swimingly' expected: 'swimingly'\n",
      " OK  got: 'do' expected: 'do'\n",
      "\n",
      "not_bad\n",
      " OK  got: 'This movie is good' expected: 'This movie is good'\n",
      " OK  got: 'This dinner is good!' expected: 'This dinner is good!'\n",
      " OK  got: 'This tea is not hot' expected: 'This tea is not hot'\n",
      " OK  got: \"It's bad yet not\" expected: \"It's bad yet not\"\n",
      "\n",
      "front_back\n",
      " OK  got: 'abxcdy' expected: 'abxcdy'\n",
      " OK  got: 'abcxydez' expected: 'abcxydez'\n",
      " OK  got: 'KitDontenut' expected: 'KitDontenut'\n"
     ]
    }
   ],
   "source": [
    "# D. verbing\n",
    "# Given a string, if its length is at least 3,\n",
    "# add 'ing' to its end.\n",
    "# Unless it already ends in 'ing', in which case\n",
    "# add 'ly' instead.\n",
    "# If the string length is less than 3, leave it unchanged.\n",
    "# Return the resulting string.\n",
    "def verbing(s):\n",
    "  length = len(s)\n",
    "\n",
    "  if length > 2:\n",
    "    if s[-3:] == 'ing':\n",
    "      s += 'ly'\n",
    "    else:\n",
    "      s += 'ing'\n",
    "\n",
    "  return s\n",
    "\n",
    "\n",
    "# E. not_bad\n",
    "# Given a string, find the first appearance of the\n",
    "# substring 'not' and 'bad'. If the 'bad' follows\n",
    "# the 'not', replace the whole 'not'...'bad' substring\n",
    "# with 'good'.\n",
    "# Return the resulting string.\n",
    "# So 'This dinner is not that bad!' yields:\n",
    "# This dinner is good!\n",
    "def not_bad(s):\n",
    "  snot = s.find('not')\n",
    "  sbad = s.find('bad')\n",
    "\n",
    "  if sbad > snot:\n",
    "    s = s.replace(s[snot:(sbad+3)], 'good')\n",
    "\n",
    "  return s\n",
    "\n",
    "\n",
    "\n",
    "# F. front_back\n",
    "# Consider dividing a string into two halves.\n",
    "# If the length is even, the front and back halves are the same length.\n",
    "# If the length is odd, we'll say that the extra char goes in the front half.\n",
    "# e.g. 'abcde', the front half is 'abc', the back half 'de'.\n",
    "# Given 2 strings, a and b, return a string of the form\n",
    "#  a-front + b-front + a-back + b-back\n",
    "def front_back(a, b):\n",
    "  alength = len(a)\n",
    "  blength = len(b)\n",
    "\n",
    "  if alength % 2 == 0:\n",
    "    aindex = alength // 2\n",
    "  else:\n",
    "    aindex = (alength // 2) + 1\n",
    "\n",
    "  if blength % 2 == 0:\n",
    "    bindex = blength // 2\n",
    "  else:\n",
    "    bindex = (blength // 2) + 1\n",
    "\n",
    "  afront = a[0:aindex]\n",
    "  aback = a[aindex:]\n",
    "\n",
    "  bfront = b[0:bindex]\n",
    "  bback = b[bindex:]\n",
    "\n",
    "  return afront + bfront + aback + bback\n",
    "\n",
    "\n",
    "# Simple provided test() function used in main() to print\n",
    "# what each function returns vs. what it's supposed to return.\n",
    "def test(got, expected):\n",
    "    if got == expected:\n",
    "        prefix = ' OK '\n",
    "    else:\n",
    "        prefix = '  X '\n",
    "    print ('%s got: %s expected: %s' % (prefix, repr(got), repr(expected)))\n",
    "    \n",
    "# main() calls the above functions with interesting inputs,\n",
    "# using the above test() to check if the result is correct or not.\n",
    "def main():\n",
    "    print ('verbing')\n",
    "    test(verbing('hail'), 'hailing')\n",
    "    test(verbing('swiming'), 'swimingly')\n",
    "    test(verbing('do'), 'do')\n",
    "\n",
    "    print()\n",
    "    print ('not_bad')\n",
    "    test(not_bad('This movie is not so bad'), 'This movie is good')\n",
    "    test(not_bad('This dinner is not that bad!'), 'This dinner is good!')\n",
    "    test(not_bad('This tea is not hot'), 'This tea is not hot')\n",
    "    test(not_bad(\"It's bad yet not\"), \"It's bad yet not\")\n",
    "\n",
    "    print()\n",
    "    print ('front_back')\n",
    "    test(front_back('abcd', 'xy'), 'abxcdy')\n",
    "    test(front_back('abcde', 'xyz'), 'abcxydez')\n",
    "    test(front_back('Kitten', 'Donut'), 'KitDontenut')\n",
    "\n",
    "if __name__ == '__main__':\n",
    "  main()\n"
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