Part1-Functional/05-FunctionParameters/03-Positional&KeywordArguments.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "f3c6c7f0",
   "metadata": {},
   "source": [
    "# Positional and Keyword Arguments"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "3f0cbd3a",
   "metadata": {},
   "source": [
    "## Posisional Arguments\n",
    "\n",
    "Most common way of assigning arguments to parameters: via the **order** in which they are passed.\n",
    "\n",
    "i.e. their **position**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "id": "09e8fbbd",
   "metadata": {},
   "outputs": [],
   "source": [
    "def my_func(a, b):\n",
    "    print(f\"{a=}, {b=}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "id": "350e86db",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=10, b=20\n"
     ]
    }
   ],
   "source": [
    "my_func(10, 20)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "id": "d7ab7b4a",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=20, b=10\n"
     ]
    }
   ],
   "source": [
    "my_func(20, 10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "id": "8d04e41a",
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "my_func() missing 1 required positional argument: 'b'",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "Cell \u001b[0;32mIn[42], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mmy_func\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;241;43m1\u001b[39;49m\u001b[43m)\u001b[49m\n",
      "\u001b[0;31mTypeError\u001b[0m: my_func() missing 1 required positional argument: 'b'"
     ]
    }
   ],
   "source": [
    "my_func(1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "id": "c7676e7d",
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "my_func() takes 2 positional arguments but 3 were given",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "Cell \u001b[0;32mIn[43], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43mmy_func\u001b[49m\u001b[43m(\u001b[49m\u001b[38;5;241;43m1\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m2\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;241;43m3\u001b[39;49m\u001b[43m)\u001b[49m\n",
      "\u001b[0;31mTypeError\u001b[0m: my_func() takes 2 positional arguments but 3 were given"
     ]
    }
   ],
   "source": [
    "my_func(1, 2, 3)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e58bf53c",
   "metadata": {},
   "source": [
    "## Default Values\n",
    "\n",
    "A positional arguments can be made **optional** by specifying a **default value** for the corresponding parameter."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "id": "74884f73",
   "metadata": {},
   "outputs": [],
   "source": [
    "def my_func(a, b=100):\n",
    "    print(f\"{a=}, {b=}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "id": "8cc20a28",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=10, b=20\n"
     ]
    }
   ],
   "source": [
    "my_func(10, 20)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "id": "ba60ec0b",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=5, b=100\n"
     ]
    }
   ],
   "source": [
    "my_func(5)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "51220d35",
   "metadata": {},
   "source": [
    "Consider a case where we have three arguments, and we want to make one of theme optional:"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "fdd35227",
   "metadata": {},
   "source": [
    "```python\n",
    "def my_func(a, b=100, c):\n",
    "    pass\n",
    "```\n",
    "\n",
    "How would we call this function without specifying a value for the second parameters?\n",
    "\n",
    "```python\n",
    "my_func(5, 25) ???\n",
    "```"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "5a972c98",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "non-default argument follows default argument (983498564.py, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[0;36m  Cell \u001b[0;32mIn[6], line 1\u001b[0;36m\u001b[0m\n\u001b[0;31m    def my_func(a, b=100, c):\u001b[0m\n\u001b[0m                          ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m non-default argument follows default argument\n"
     ]
    }
   ],
   "source": [
    "def my_func(a, b=100, c):\n",
    "    pass"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "d09662c8",
   "metadata": {},
   "source": [
    "If a positional parameter is defined with a didault value\n",
    "    \n",
    "**every** positional parameter after it\n",
    "\n",
    "**must** also be given a difault value."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "id": "c525980e",
   "metadata": {},
   "outputs": [],
   "source": [
    "def my_func(a, b=5, c=10):\n",
    "    print(f\"{a=}, {b=}, {c=}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "id": "f2bfbc75",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=5, c=10\n"
     ]
    }
   ],
   "source": [
    "my_func(1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "id": "1b9d29c4",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=2, c=10\n"
     ]
    }
   ],
   "source": [
    "my_func(1, 2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "id": "a59a2517",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=2, c=3\n"
     ]
    }
   ],
   "source": [
    "my_func(1, 2, 3)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0aa7a2c3",
   "metadata": {},
   "source": [
    "But what if we want to specify $1^{st}$ and $3^{rd}$ arguments, but omit the $2^{nd}$ argument?\n",
    "\n",
    "i.e. we want to specify values for `a` and `c`, but let `b` take on its difault value?"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "2ae0f362",
   "metadata": {},
   "source": [
    "## Keyword Arguments (named argumnets)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "id": "a80ba0f7",
   "metadata": {},
   "outputs": [],
   "source": [
    "def my_func(a, b=5, c=10):\n",
    "    print(f\"{a=}, {b=}, {c=}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "id": "55dc2a6a",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=5, c=2\n"
     ]
    }
   ],
   "source": [
    "my_func(a=1, c=2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "id": "81bb6427",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=5, c=2\n"
     ]
    }
   ],
   "source": [
    "my_func(1, c=2)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "759ca484",
   "metadata": {},
   "source": [
    "Positional arguments can, **optionally**, be specified by using the parameter name.\n",
    "\n",
    "Whether or not the parameters have default values"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "a96816cf",
   "metadata": {},
   "outputs": [],
   "source": [
    "def my_func(a, b, c):\n",
    "    # code hare\n",
    "    pass"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "a2666893",
   "metadata": {},
   "source": [
    "```python\n",
    "my_func(1, 2, 3)\n",
    "my_func(1, 2, c=3)\n",
    "my_func(a=1, b=2, c=3)\n",
    "my_func(c=3, a=1, b=2)\n",
    "```\n",
    "\n",
    "`a = 1`, `b = 2`, `c = 3`"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "4df3ee0e",
   "metadata": {},
   "source": [
    "But once you use a named argument, all parameters **thereafter must** be named too."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "dae4ac29",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "positional argument follows keyword argument (3895868150.py, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[0;36m  Cell \u001b[0;32mIn[5], line 1\u001b[0;36m\u001b[0m\n\u001b[0;31m    my_func(c=1, 2, 3)\u001b[0m\n\u001b[0m                     ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m positional argument follows keyword argument\n"
     ]
    }
   ],
   "source": [
    "my_func(c=1, 2, 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "ca08245f",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "positional argument follows keyword argument (2003381380.py, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[0;36m  Cell \u001b[0;32mIn[6], line 1\u001b[0;36m\u001b[0m\n\u001b[0;31m    my_func(1, b=2, 3)\u001b[0m\n\u001b[0m                     ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m positional argument follows keyword argument\n"
     ]
    }
   ],
   "source": [
    "my_func(1, b=2, 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "id": "f1e2d0ba",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=2, c=3\n"
     ]
    }
   ],
   "source": [
    "my_func(1, 2, c=3)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "81b049f3",
   "metadata": {},
   "source": [
    "All arguments after the first named (keyword) arguments, must be named too.\n",
    "\n",
    "Default arguments may still ne omitted."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "id": "d1ef5052",
   "metadata": {},
   "outputs": [],
   "source": [
    "def my_func(a, b=2, c=3):\n",
    "    print(f\"{a=}, {b=}, {c=}\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "id": "fd0236b5",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=2, c=3\n"
     ]
    }
   ],
   "source": [
    "my_func(1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "id": "2bc17243",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=5, c=3\n"
     ]
    }
   ],
   "source": [
    "my_func(a=1, b=5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "id": "0a95be80",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a=1, b=2, c=0\n"
     ]
    }
   ],
   "source": [
    "my_func(c=0, a=1)"
   ]
  }
 ],
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