00 / 30 : add pathlib example

Clean ipynb b487e2b

00_introduction/30_python_review_2.ipynb

@@ -721,6 +721,79 @@
     "\n"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## File I/O\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "### `pathlib`\n",
+    "* `pathlib` : Object oriented file system paths in the python standard library<br>파이썬 표준 라이브러리 내 객체 지향 파일 경로\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import pathlib\n",
+    "\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# pathlib.Path to a possible new temporary folder\n",
+    "tmp_path = pathlib.Path('temporary_folder')\n",
+    "\n",
+    "# create the new temporary folder\n",
+    "#   exist_ok: no \"folder already exists\" error even if the folder is already there\n",
+    "tmp_path.mkdir(exist_ok=True)\n",
+    "\n",
+    "# pathlib.Path to a possible new file\n",
+    "new_file = tmp_path / 'my_new_file.txt'\n",
+    "\n",
+    "bytes_written = 0\n",
+    "\n",
+    "# open the file in text write mode\n",
+    "with new_file.open('wt', encoding='utf-8') as tmp_file:\n",
+    "    for i in range(10):\n",
+    "        # write a text line to the temporary file\n",
+    "        bytes_written += tmp_file.write(f'i = {i} i*i = {i*i}\\n')\n",
+    "# file closed\n",
+    "\n",
+    "print(f'bytes_written = {bytes_written}')\n",
+    "\n",
+    "bytes_read = 0\n",
+    "# open the temporary file in text read mode\n",
+    "with new_file.open('rt', encoding='utf-8') as read_file:\n",
+    "    # iterating through a file will fetch one line at a time\n",
+    "    for k, line in enumerate(read_file):\n",
+    "        txt = f'line {k:2d} : {line}'\n",
+    "        print(txt)\n",
+    "        bytes_read += len(line)\n",
+    "# file closed\n",
+    "\n",
+    "print(f'bytes_read = {bytes_read}')\n",
+    "\n",
+    "# when the task is done, remove the file & folder\n",
+    "new_file.unlink()\n",
+    "# works only when the folder is empty\n",
+    "tmp_path.rmdir()\n",
+    "\n"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -770,7 +843,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.10.0"
+   "version": "3.10.9"
   }
  },
  "nbformat": 4,