{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Tips About Accessing Element Attributes of `Series`"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "`Series` combins data.\n",
    "When `Series` combines same **type** data, the `Series` will become a container to access data `attributes`.\n",
    "So this type of `Series` could be call a `string` type of `Series`, a `Path` type of `Series`, a `CRS` type of `Series` and more."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Are there any ways to access data attributes of `Series`?\n",
    "\n",
    "- Use `apply` method to fetch attributes.\n",
    "- Use Pandas Object Accessor, `pandas.api.extensions.register_series_accessor`.\n",
    "- Use `getattr`, `dtoolkit.accessor.series.getattr`."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Use `apply` Method\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `apply` Method's String Example"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import pandas as pd\n",
    "\n",
    "s = pd.Series([\"hello\", \"world\"])\n",
    "s"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Count the `'l'` number."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.apply(lambda x: x.count(\"l\"))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Find the `'l'`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.apply(lambda x: x.find(\"l\"))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Return the element length."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.apply(lambda x: len(x))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `apply` Method Conclusion"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "From above example, we could see:\n",
    "\n",
    "- advantages\n",
    "  - doesn't need to pre-code firstly\n",
    "  - support to return arbitrary result via `lambda` function\n",
    "- disadvantages\n",
    "  - bad code style, need to key in a lot of nonsense codes"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Use Pandas Object Accessor"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "For convenience, `Pandas` does a `.str` accessor to access `string` attributes for `string` type of `Series`."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `.str` Accessor's String Example"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Count the `'l'` number."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.str.count(\"l\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Find the `'l'`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.str.find(\"l\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Return the element length."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.str.len()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Accessor Method Conclusion"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "From above example, we could see:\n",
    "\n",
    "- advantages\n",
    "  - keep the same code style, `'a string'.count()` & `Series.str.count()`\n",
    "  - support to add additional attributes, `'a string'.__len__()` -> `Series.str.len()`\n",
    "- disadvantages\n",
    "  - need to pre-code firstly"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Use `getattr`"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Let us quickly glance `getattr` example to show."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `getattr`'s String Example"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import dtoolkit"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Count the `'l'` number."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.getattr(\"count\", \"l\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Find the `'l'`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.getattr(\"find\", \"l\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Return the element length."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "s.getattr(\"__len__\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `getattr` Method Conclusion"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "From above example, we could see:\n",
    "\n",
    "- advantages\n",
    "  - doesn't need to pre-code firstly\n",
    "- disadvantages\n",
    "  - not OOP style but functional style, a little bit weird for switching two different styles.\n",
    "  - doesn't support calling attributes that don't exist."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Summary"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Compare these methods, we can get ranking at different backgrounds.\n",
    "\n",
    "- Flexibility / Scalability: accessor > `apply` > `getattr`\n",
    "- Ease of use\n",
    "  - With pre-code accessor: accessor > `getattr` > `apply`\n",
    "  - Without pre-code accessor: `getattr` > `apply`"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The aim of `getattr` is to quickly access element attributes of `Series` attributes without more codes.\n",
    "\n",
    "Base on that, it could quickly fetch attributes from Series element.\n",
    "\n",
    "So it is a minimal accessor to Series."
   ]
  }
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