Python for and while loop

Python for and while loop.ipynb

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   "source": [
    "This is a summary of the [\"How to change index of for loop in Python?\n",
    "\"](https://stackoverflow.com/questions/14785495/how-to-change-index-of-for-loop-in-python) post on Stackoverflow."
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   "source": [
    "### Problem\n",
    "\n",
    "I want to change the value of i in a for loop:"
   ]
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   "source": [
    "for i in range(5):\n",
    "    print(i)\n",
    "    i += 2"
   ]
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   "source": [
    "The value of i does not change in a for loop, becaue"
   ]
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   "source": [
    "### The essense of a for loop"
   ]
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "```python\n",
    "for i in iterable: \n",
    "    # some code with i\n",
    "```\n",
    "\n",
    "is a shorthand for\n",
    "\n",
    "```python\n",
    "iterator = iter(iterable)\n",
    "while True:\n",
    "    try:\n",
    "        i = next(iterator)  # i is reassigned at the beginning of every iteration         \n",
    "    except StopIteration:\n",
    "        break\n",
    "    # some code with i\n",
    "```"
   ]
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "`while` should be used instead if you intend to change the value of i:"
   ]
  },
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   "execution_count": 6,
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    {
     "name": "stdout",
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     "text": [
      "0\n",
      "2\n",
      "4\n"
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   ],
   "source": [
    "i = 0\n",
    "while i < 6:\n",
    "    print(i)\n",
    "    i+=2"
   ]
  }
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