Merge pull request #61 from DurhamARC-Training/functions_and_formatting_improvement_spring_2026

Functions and formatting improvement spring 2026

Author: taflynn

Basics.ipynb

@@ -1189,7 +1189,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "2f3d5124",
+   "id": "c1b5c739",
    "metadata": {
     "editable": false,
     "slideshow": {
@@ -1198,33 +1198,26 @@
     "tags": []
    },
    "source": [
-    "## Interlude: Indented blocks in python\n",
-    "Python uses indention to separate blocs after a `:`\n",
-    "```python\n",
-    "some_functionality_on_block:\n",
-    "   first_statement_in_block()\n",
-    "   second_statement_in_block()\n",
-    "statement_not_in_block()\n",
-    "```\n"
+    "# <ins>2.</ins> Functions"
    ]
   },
   {
    "cell_type": "markdown",
-   "id": "c1b5c739",
+   "id": "3f6b80d9",
    "metadata": {
     "editable": false,
     "slideshow": {
-     "slide_type": "slide"
+     "slide_type": ""
     },
     "tags": []
    },
    "source": [
-    "# <ins>2.</ins> Functions"
+    "A function is a block of reusable code that performs a specific task. Functions help reduce repetition and make code easier to manage."
    ]
   },
   {
    "cell_type": "markdown",
-   "id": "3f6b80d9",
+   "id": "383ac2a1",
    "metadata": {
     "editable": false,
     "slideshow": {
@@ -1233,23 +1226,67 @@
     "tags": []
    },
    "source": [
-    "A function is a block of reusable code that performs a specific task. Functions help reduce repetition and make code easier to manage. A function is defined using the `def` keyword."
+    "* You can pass data to functions (parameters).\n",
+    "* Functions can return values.\n",
+    "* Functions help break down complex programs into smaller, manageable parts."
    ]
   },
   {
    "cell_type": "markdown",
-   "id": "383ac2a1",
+   "id": "ca147ce4",
+   "metadata": {
+    "editable": false
+   },
+   "source": [
+    "We have already encountered a function - `print`. Here are some more examples:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "d1f13779",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "positive = abs(-42)\n",
+    "print(positive)\n",
+    "\n",
+    "# We've also encountered type(), but what about if we *change* the type of a variable?\n",
+    "stringified = str(42)\n",
+    "type_of_stringified = type(stringified)\n",
+    "print(type_of_stringified)\n",
+    "print(stringified == \"42\")\n",
+    "\n",
+    "# Hey look, it's floating! Just like a dolphin!\n",
+    "floatified = float(42)\n",
+    "print(floatified)\n",
+    "\n",
+    "# Functions can take multiple arguments, separated, by, commas:\n",
+    "numbers = range(3, 10)\n",
+    "sum_of_numbers = sum(numbers)\n",
+    "print(sum_of_numbers)\n",
+    "\n",
+    "\n",
+    "# What's That Keyword? (We're not going to talk about that keyword (today))\n",
+    "import random\n",
+    "\n",
+    "random_number = random.randint(0, 100)\n",
+    "print(random_number)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "696b6e90",
    "metadata": {
-    "editable": false,
     "slideshow": {
-     "slide_type": ""
+     "slide_type": "slide"
     },
-    "tags": []
+    "editable": false
    },
    "source": [
-    "* You can pass data to functions (parameters).\n",
-    "* Functions can return values.\n",
-    "* Functions help break down complex programs into smaller, manageable parts."
+    "We can make functions with our own code as well.\n",
+    "\n",
+    "A function is defined using the `def` keyword:"
    ]
   },
   {
@@ -1264,16 +1301,66 @@
     "tags": []
    },
    "outputs": [],
+   "source": [
+    "# Function to add two numbers and print it out\n",
+    "def add_numbers(a, b):\n",
+    "    print(a + b)\n",
+    "\n",
+    "# Call the function\n",
+    "add_numbers(3, 4)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "ddd2d577",
+   "metadata": {
+    "editable": false
+   },
+   "source": [
+    "To get a value out of a function, we use the `return` keyword:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "0c93d094",
+   "metadata": {},
+   "outputs": [],
    "source": [
     "# Function to add two numbers\n",
     "def add_numbers(a, b):\n",
-    "    return a + b\n",
+    "    total = a + b\n",
+    "    return total\n",
     "\n",
     "# Call the function\n",
-    "result = add_numbers(3, 4)\n",
+    "result = add_numbers(17, 25)\n",
     "print(result)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "09668f03",
+   "metadata": {
+    "slideshow": {
+     "slide_type": "slide"
+    },
+    "editable": false
+   },
+   "source": [
+    "## Interlude: Indented blocks in python\n",
+    "Python uses indentation to separate blocs after a `:`\n",
+    "```python\n",
+    "def this_is_a_function(my_number):\n",
+    "   if my_number == 42:\n",
+    "      print(\"You already got it!\")\n",
+    "      return my_number\n",
+    "\n",
+    "   the_answer = my_number + 42\n",
+    "   return the_answer\n",
+    "```\n",
+    "Indentation is done with 2 or 4 spaces, and many editors will map the `TAB` key to insert spaces rather than a tab character."
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "2a8095f4",
@@ -1301,12 +1388,39 @@
    "source": [
     "### _Exercises_\n",
     "\n",
-    "**1)** Write a function that converts Celsius to Fahrenheit. Use the formula  \n",
+    "**1)** Use the `add_numbers` function to convert Celsius to Fahrenheit. Use the formula  \n",
     "$\n",
     "\\text{Fahrenheit} = (\\text{Celsius} \\times \\frac{9}{5}) + 32\n",
     "$"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b7dd742f",
+   "metadata": {
+    "editable": true,
+    "remove_code": "after:# Convert to fahrenheit:"
+   },
+   "outputs": [],
+   "source": [
+    "# The temperature in Celsius\n",
+    "celsius = 20\n",
+    "\n",
+    "# Convert to fahrenheit:\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "5297733c",
+   "metadata": {
+    "editable": false
+   },
+   "source": [
+    "\n",
+    "**2)** Write a function of your own that converts Celsius to Fahrenheit."
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -1420,6 +1534,26 @@
     "print(\"Hello \" + name)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "12d99e16",
+   "metadata": {
+    "editable": false
+   },
+   "source": [
+    "## Interlude: String Formatting\n",
+    "\n",
+    "Python has a magic thing called `f-strings` (formatted string literals), which occur when you prefix a string with the letter `f`:\n",
+    "```python\n",
+    "f\"This is an f-string! But it doesn't do anything special yet...\n",
+    "```\n",
+    "This magic allows us to format variables of different types into a string, letting us write them out concisely. We do this by putting an expression inside curly { braces } inside the f-string:\n",
+    "```python\n",
+    "number = 10\n",
+    "print(f\"My number is {number}!\")\n",
+    "```"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "81998d75",
@@ -1470,7 +1604,7 @@
     "tags": []
    },
    "source": [
-    "### Writing files and formatting strings (C-style)"
+    "### Writing files"
    ]
   },
   {
@@ -1488,25 +1622,11 @@
     "with open(\"testfile.txt\", \"w\") as my_file:\n",
     "    # Write - note special characters!\n",
     "    my_file.write(\"This is some text. \\n And some more.\")\n",
-    "    my_file.write(\"\\n\\nI can also add numbers like this: %d %d \\n\" %(22, 333))\n",
+    "    my_file.write(f\"\\n\\nI can also write a number: {42}\\n\")\n",
     "\n",
     "    my_file.write(str(222))"
    ]
   },
-  {
-   "cell_type": "markdown",
-   "id": "0d884b3f",
-   "metadata": {
-    "editable": false,
-    "slideshow": {
-     "slide_type": ""
-    },
-    "tags": []
-   },
-   "source": [
-    "see also [https://www.learnpython.org/en/String\\_Formatting](https://www.learnpython.org/en/String_Formatting)"
-   ]
-  },
   {
    "cell_type": "markdown",
    "id": "16c995a4",
@@ -1518,7 +1638,7 @@
     "tags": []
    },
    "source": [
-    "### Writing files (f-strings)"
+    "### Writing files (append mode)"
    ]
   },
   {
@@ -1534,26 +1654,12 @@
    },
    "outputs": [],
    "source": [
-    "number1 = 44\n",
+    "number1 = 42\n",
     "number2 = 111\n",
     "\n",
     "with open(\"testfile.txt\", \"a\") as my_file:\n",
     "    # Append to the opened file\n",
-    "    my_file.write(f\"\\n I have opened the same file again.\\n More numbers: {number1} {number2}.\")"
-   ]
-  },
-  {
-   "cell_type": "markdown",
-   "id": "4db7b7e2",
-   "metadata": {
-    "editable": false,
-    "slideshow": {
-     "slide_type": ""
-    },
-    "tags": []
-   },
-   "source": [
-    "see also [f-strings](https://realpython.com/python-f-strings/)"
+    "    my_file.write(f\"\\nI have opened the same file again.\\nMore numbers: {number1} {number2}.\")"
    ]
   },
   {
@@ -3463,7 +3569,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "Python 3",
    "language": "python",
    "name": "python3"
   },
@@ -3477,7 +3583,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.13.2"
+   "version": "3.14.3"
   }
  },
  "nbformat": 4,