230_Files.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Files\n",
    "\n",
    "Files are extremely important in Python. They are using in caching, data storage, reading data and more. There are lots of ways to work with files in Python, but we'll stick with the basics in this notebook."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Creating a new file"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "with open(\"230_files_test.txt\", \"w\") as f:\n",
    "    f.write(\"Hello world, this is our first programmatically created file\")\n",
    "    f.close() "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "> **Note**: Notice the use of `open()` and the keywords **with** and **as**. Also note the use of **indentation** here."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Reading a file"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "<class '_io.TextIOWrapper'>\n"
     ]
    }
   ],
   "source": [
    "with open(\"230_files_test.txt\", \"r\") as f:\n",
    "    print(type(f))\n",
    "    contents = f.read()\n",
    "    f.close()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "HELLO FROM VS CODE\n",
      "\n"
     ]
    }
   ],
   "source": [
    "print(contents)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [],
   "source": [
    "with open(\"230_files_test.txt\", \"w\") as f:\n",
    "    f.write(\"New file stuff\")\n",
    "    f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Appending data to an existing file"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [],
   "source": [
    "with open(\"230_files_test.txt\", \"a\") as f:\n",
    "    f.write(\"\\nThis is line 4 from Kalob\")\n",
    "    f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Looping through data in a file\n",
    "\n",
    "First we need to open the file and save the data in a variable outside of the \"file\" area. \n",
    "\n",
    "Then we can loop through every line in the file and print it out. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "f.name =>  230_files_test.txt\n"
     ]
    }
   ],
   "source": [
    "with open(\"230_files_test.txt\", \"r\") as f:\n",
    "    print(\"f.name => \", f.name)\n",
    "    lines = f.readlines()\n",
    "    f.close()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['New file stuff\\n',\n",
       " 'This is line 2\\n',\n",
       " 'This is line 3\\n',\n",
       " 'This is line 4 from Kalob']"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "lines"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "list"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "type(lines)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "New file stuff\n",
      "\n",
      "This is line 2\n",
      "\n",
      "This is line 3\n",
      "\n",
      "This is line 4 from Kalob\n"
     ]
    }
   ],
   "source": [
    "for line in lines:\n",
    "    print(line)"
   ]
  }
 ],
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