python-intro/exercises/ex14_variable_scope.ipynb

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    "# Exercise 14: Variable Scope"
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   "source": [
    "## Aim: Learn about local and global variables."
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    "### Issues covered:\n",
    "- Learn the difference between local and global variables\n",
    "- Make sure to define variables in the right scope\n",
    "- Learn to locate where errors are using the traceback"
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    "## 1. Let's take a look at local variables"
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    "What is the problem with the program below? Fix the error to print out the temperature.\n",
    "```\n",
    "change = 1.0\n",
    "\n",
    "def change_temperature(change):\n",
    "    temperature = 100 - change\n",
    "    return temperature\n",
    "\n",
    "print(temperature)\n",
    "```"
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   "source": [
    "## 2. Let's investigate the difference between local and global variables."
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    "Run the block of code below. Do you know why the value of temperature doesn't change? How can you make the value of temperature reflect the changes from the `change_temperature` function?\n",
    "```\n",
    "temperature = 100\n",
    "\n",
    "def change_temperature():\n",
    "    temperature = 0\n",
    "    return temperature\n",
    "\n",
    "print(temperature)\n",
    "change_temperature()\n",
    "print(temperature)\n",
    "```"
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    "## 3. Let's take a look at some error messages and learn to understand them"
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    "What is the issue with this block of code? Take a look at the type of error and the error message given.\n",
    "```\n",
    "def print_friday_message():\n",
    "    print_message(\"Friday\")\n",
    "\n",
    "print_friday_message()\n",
    "```"
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    "Define a function called `print_message` which has the day as an argument and prints \"Today is <day>\" for any day given. Then write a new function called `print_friday_message` which uses `print_message` to print \"Today is Friday\". Does this run without an error now?"
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