python-intro/exercises/ex11_conditionals.ipynb

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    "# Exercise 11: Conditionals"
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   "source": [
    "## Aim: Learn to use `if` and `else` statements."
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    "### Issues covered:\n",
    "- Taking a look at an `if` `else` block\n",
    "- Writing an `if` block\n",
    "- Writing an `if` `elif` block"
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    "## 1. Let's take a look at an `if` `else` block:"
   ]
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    "Copy the code below and experiment with changing the values of the mass and acceleration:\n",
    "```\n",
    "mass = 0.5\n",
    "acceleration = 1.0\n",
    "force = mass * acceleration\n",
    "if force < 1:\n",
    "    print(\"Force is small.\")\n",
    "else:\n",
    "    print(\"Force is big.\")\n",
    "```"
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    "What happens if you make the force exactly equal to 1?"
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   "source": [
    "## 2. Let's write some `if` `elif` blocks"
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   "source": [
    "Create a variable called `name` assigned the value 'Lisa'. Write an `if` block that prints 'plays a saxophone' if someone's name is Lisa."
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    "Add an `elif` block that tests if `name` is Bart. If so, print 'rides a skateboard.'."
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    "Add an `else` block which prints 'lives in Springfield' for any other names given."
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    "## 3. Let's try a harder task of looping through some files"
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    "Write a program which loops through all files in the data folder and prints out the length of those with more than 10 records."
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    "Hint: Use the package `glob` to help loop through the data files, with the syntax `glob.glob(data/*.csv')`, and `pandas` to read the data as in previous exercises. We'll take a closer look at `glob` next lesson."
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    "## 4. Extension: `while` loops."
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   "source": [
    "There is another type of conditional called `while` that hasn't been covered. "
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    "1. You can create a `while` loop using:\n",
    "```\n",
    "i = 1\n",
    "while i < 10:\n",
    "    print(i)\n",
    "```\n",
    "But be careful - this loop never ends as the value of `i` doesn't change so will keep running forever! Make sure you know how to stop the cell running to escape. You can do this by hitting the stop button to interrupt the kernel. \n",
    "Copy this code below but add a line of code that increments `i` by 1 in the loop so that it doesn't run indefinetly."
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    "2. Create a variable called `gases` assigned the list `['He', 'Ne', 'Ar', 'Kr']"
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    "3. Create a while loop which prints each item in the list.\n",
    "- Create a `count` variable which starts at 0.\n",
    "- Create the `while` loop.\n",
    "- Print `gases[count]`\n",
    "- Increment the count by 1."
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