python-intro/solutions/ex02_variables_assignment.ipynb

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   "source": [
    "# Exercise 2: Variables and assignment"
   ]
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  {
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   "id": "34ea004d-f444-429f-98e5-7182e554b540",
   "metadata": {},
   "source": [
    "## Aim: Introduce Python variables and perform calculations with them."
   ]
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   "source": [
    "### Issues covered:\n",
    "- Creating variables\n",
    "- Simple arithmetic\n",
    "- Using `print` to display variables\n",
    "- Looking at strings"
   ]
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   "cell_type": "markdown",
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   "source": [
    "## 1. Let's create some variables and print their values"
   ]
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   "source": [
    "Create a variable called `course` and assign it the value `\"python\"`."
   ]
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    "course = \"python\""
   ]
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   "metadata": {},
   "source": [
    "Create a variable called `rating` and assign it an integer value of your choice."
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    "rating = 0"
   ]
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   "source": [
    "Print these variables to your screen using the `print` function."
   ]
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     "text": [
      "python 0\n"
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   "source": [
    "print(course, rating)"
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   "id": "caabe048-f40c-4406-a97f-8940ffd75c1e",
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   "source": [
    "Try printing the values without using the `print` function. "
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   "source": [
    "_Note: This method works in notebooks, however in a script you will need to use `print`._"
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       "('python', 0)"
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    "course, rating"
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   "source": [
    "## 2. Let's use Pythagoras' Theorem to calculate the length of the hypotenuse of a right-angled triangle where the other sides have lengths 3 and 4."
   ]
  },
  {
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   "id": "cec659bc-495f-43a7-9b8a-8f5ce2ef45c8",
   "metadata": {},
   "source": [
    "Create variables called `b` and `c` and assign them the values of the sides with known lengths."
   ]
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   "source": [
    "b = 3\n",
    "c = 4"
   ]
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   "source": [
    "We can use variables in calculations - try writing a mathematical expression to calculate the length of the hypotenuse."
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   "source": [
    "_Hint: Remember Pythagoras' Theorem: $a^2$ = $b^2$ + $c^2$_"
   ]
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       "5.0"
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    "(b**2 + c**2) ** 0.5"
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   "source": [
    "If you haven't already, create a variable `a` and set its value to the result of the calculation."
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   "source": [
    "a = (b**2 + c**2) ** 0.5"
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   "source": [
    "Print the value of `a`."
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      "5.0\n"
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   "source": [
    "print(a)"
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   "source": [
    "## 3. Let's extract some data from strings."
   ]
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   "id": "354aa762-187e-4acd-8ceb-ff64868b9352",
   "metadata": {},
   "source": [
    "Create a string variable with the value `Centre for Environmental Data Analysis`. How many letters are in this string?"
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     "text": [
      "38\n"
     ]
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   "source": [
    "my_string = \"Centre for Environmental Data Analysis\"\n",
    "print(len(my_string))"
   ]
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   "id": "0bb0bc7b-472a-463c-81f0-6c5faad2caba",
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   "source": [
    "What is the 30th character of this string? _Hint: You should get \" \"_."
   ]
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     "name": "stdout",
     "output_type": "stream",
     "text": [
      " \n"
     ]
    }
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   "source": [
    "# Slightly a trick question - the 30th character is the 29th in Python as indexing starts from 0.\n",
    "print(my_string[29])"
   ]
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   "source": [
    "If you take a slice from the 11th to 24th characters, what does this say?"
   ]
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     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Environmental\n"
     ]
    }
   ],
   "source": [
    "print(my_string[11:24])"
   ]
  },
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   "id": "41f6c7a8-eb2b-4f09-9042-003dcf48b4d5",
   "metadata": {},
   "source": [
    "Return only `Data Analysis` from the string. _Hint: The D in Data is the 26th character_."
   ]
  },
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     "name": "stdout",
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     "text": [
      "Data Analysis\n"
     ]
    }
   ],
   "source": [
    "print(my_string[25:])"
   ]
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