week4-2practice.ipynb

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   "source": [
    "### Lecture 4-2 Practice: Creating our own iterator."
   ]
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   "source": [
    "### Question 1\n",
    "Implement a custom range iterator class called MyRange that mimics some of the basic functionality of Python's built-in range() function. This exercise will help you understand how iterators work in Python.\n",
    "\n",
    "1. Create a class named MyRange that takes two integer arguments in its constructor:\n",
    "start: the first value of the range\n",
    "end: the value to stop before (exclusive)\n",
    "\n",
    "2. The class should implement the iterator protocol, making it usable in a for loop.\n",
    "\n",
    "3. Each iteration should return the next integer in the sequence, starting from start and incrementing by 1 each time.\n",
    "The iteration should stop when the value would become equal to or greater than end."
   ]
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   "source": [
    "class MyRange:\n",
    "    # YOUR CODE HERE"
   ]
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   "source": [
    "# MyRange should work as an iterator\n",
    "nums = MyRange(1, 5)\n",
    "for num in nums:\n",
    "    print(num)"
   ]
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   "source": [
    "nums = MyRange(1, 5)\n",
    "print(next(nums))\n",
    "print(next(nums))\n",
    "print(next(nums))\n",
    "print(next(nums))"
   ]
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   "source": [
    "### Question 2\n",
    "Create the same custom iterators in Python using generator-based approach."
   ]
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   "execution_count": 29,
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   "source": [
    "def harmonic():\n",
    "    (h,n) = (0,1)\n",
    "    while True:\n",
    "        (h,n) = (h+1/n,n+1)\n",
    "        yield h"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1.0, 1.5, 1.8333333333333333, 2.083333333333333]"
      ]
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     "execution_count": 30,
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   "source": [
    "h = harmonic()\n",
    "[next(h) for _ in range(4)]"
   ]
  },
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   "cell_type": "code",
   "execution_count": 41,
   "metadata": {},
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   "source": [
    "def my_range(start,end):\n",
    "    count = start\n",
    "    while count < end:\n",
    "        yield count\n",
    "        count += 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "metadata": {},
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     "text": [
      "1\n",
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "nums = my_range(1, 5)\n",
    "for num in nums:\n",
    "    print(num)"
   ]
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      "1\n",
      "2\n",
      "3\n",
      "4\n"
     ]
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   ],
   "source": [
    "nums = my_range(1, 5)\n",
    "print(next(nums))\n",
    "print(next(nums))\n",
    "print(next(nums))\n",
    "print(next(nums))"
   ]
  },
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   "metadata": {},
   "source": [
    "### Question 3\n",
    "\n",
    "Write a function add_grade(subject, grade) that handles grade input validation with the following requirements:"
   ]
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   "source": [
    "def add_grade(subject, grade):\n",
    "    \"\"\"\n",
    "    Add a grade for a subject. \n",
    "    Requirements:\n",
    "    - Convert grade input to float\n",
    "    - Grade must be between 0 and 100\n",
    "    - Print success message if grade is valid\n",
    "    - Handle invalid inputs appropriately\n",
    "    \"\"\"\n",
    "    grades = {}\n",
    "    # YOUR CODE HERE\n",
    "            \n",
    "# Test cases - DO NOT MODIFY\n",
    "add_grade(\"Math\", 85)          # Should succeed\n",
    "add_grade(\"Physics\", \"abc\")    # Should handle ValueError\n",
    "add_grade(\"Chemistry\", 150)    # Should handle out-of-range\n",
    "add_grade(\"Biology\", -5)       # Should handle negative values"
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