13.List Comprehensions.ipynb

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        "#Comprehensions\n",
        "\n",
        "In addition to sequence operations and list methods, Python includes a more advanced operation called a list comprehension.\n",
        "\n",
        "List comprehensions allow us to build out lists using a different notation. You can think of it as essentially a one line for loop built inside of brackets. For a simple example:\n",
        "##Example 1"
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      "source": [
        "# Grab every letter in string\n",
        "lst = [x for x in 'word']"
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        "# Check\n",
        "lst"
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      "source": [
        "This is the basic idea of a list comprehension. If you're familiar with mathematical notation this format should feel familiar for example: x^2 : x in { 0,1,2...10} \n",
        "\n",
        "Lets see a few more example of list comprehensions in Python:\n",
        "##Example 2"
      ]
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      "source": [
        "# Square numbers in range and turn into list\n",
        "lst = [x**2 for x in range(0,11)]"
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      "source": [
        "##Example 3\n",
        "Lets see how to add in if statements:"
      ]
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        "# Check for even numbers in a range\n",
        "lst = [x for x in range(11) if x % 2 == 0]"
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      "source": [
        "##Example 4\n",
        "Can also do more complicated arithmetic:"
      ]
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      "source": [
        "# Convert Celsius to Fahrenheit\n",
        "celsius = [0,10,20.1,34.5]\n",
        "\n",
        "fahrenheit = [ ((float(9)/5)*temp + 32) for temp in Celsius ]\n",
        "\n",
        "fahrenheit"
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      "source": [
        "##Example 5\n",
        "We can also perform nested list comprehensions, for example:"
      ]
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        "lst = [ x**2 for x in [x**2 for x in range(11)]]\n",
        "lst"
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      "source": [
        "## **Challenge Problem**  [Hackerrank : List Comprehensions](https://www.hackerrank.com/challenges/list-comprehensions/problem)  \n",
        "[Solution](https://www.hackerrank.com/challenges/list-comprehensions/editorial)"
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      "source": [
        "Later on in the course we will learn about generator comprehensions. After this lecture you should feel comfortable reading and writing basic list comprehensions."
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