Basic Python/2-Built-in-functions-finished.ipynb

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   "source": [
    "# Built-in Functions"
   ]
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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Python comes with a wide range of functions. However many of these are part of stanard libraries like the `math` library rather than built-in."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Converting values\n",
    "\n",
    "Conversion from hexadecimal to decimal is done by adding prefix **0x** to the hexadecimal value or vice versa by using built in **hex( )**, Octal to decimal by adding prefix **0** to the octal value or vice versa by using built in function **oct( )**."
   ]
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   "source": [
    "hex(150)"
   ]
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     "data": {
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   "source": [
    "0x96"
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   "cell_type": "markdown",
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   "source": [
    "**int( )** converts a number to an integer. \n",
    "This can be decimal numbers, integer or a string. For strings the base can optionally be specified:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "9 9 9\n"
     ]
    }
   ],
   "source": [
    "print(int(9.9) , int('1001',2) , int('9') )"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**str()** function can be used to convert almost anything to a string."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "True\n",
      "1.234\n",
      "-2\n"
     ]
    }
   ],
   "source": [
    "print(str(True))\n",
    "print(str(1.234))\n",
    "print(str(-2))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Mathematical functions\n",
    "Mathematical functions include the usual suspects like logarithms, trigonometric fuctions, the constant $\\pi$ and so on."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1.0"
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     "execution_count": 5,
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   ],
   "source": [
    "import math\n",
    "math.sin(math.pi/2)\n",
    "from math import * # avoid having to put a math. in front of every mathematical function\n",
    "sin(pi/2) # equivalent to the statement above"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Simplifying Arithmetic Operations"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**round( )** function rounds the input value to a specified number of places or to the nearest integer. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "6\n",
      "4.56\n"
     ]
    }
   ],
   "source": [
    "print( round(5.6231) )\n",
    "print( round(4.55892, 2) )"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "complex( ) is used to define a complex number and abs( ) outputs the absolute value of the same. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "5.385164807134504\n"
     ]
    }
   ],
   "source": [
    "c =complex('5+2j')\n",
    "print( abs(c) )"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**divmod(x,y)** function outputs the quotient and the remainder in a tuple in the format (quotient, remainder). "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
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     "data": {
      "text/plain": [
       "(3, 0)"
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     "execution_count": 8,
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   ],
   "source": [
    "divmod(9,3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Accepting User Inputs"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**input(prompt)**,  prompts for and returns input as a string. A useful function to use in conjunction with this is **eval()** which takes a string and evaluates it as a python expression."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "abc = 1+3\n",
      "some expression: 2+4\n",
      "1+3 6\n"
     ]
    }
   ],
   "source": [
    "abc =  input(\"abc = \")\n",
    "\n",
    "a=eval(input('some expression: '))\n",
    "\n",
    "print(abc , a)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The **print()** function prints all of its arguments as strings, separated by spaces and follows by a linebreak:\n",
    "\n",
    "    - print(\"Hello World\")\n",
    "    - print(\"Hello\",'World')\n",
    "    - print(\"Hello\", <Variable Containing the String>)\n",
    "\n",
    "Note that **print** is different in old versions of Python (2.7) where it was a statement and did not need parenthesis around its arguments."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Hello World\n"
     ]
    }
   ],
   "source": [
    "print(\"Hello\",\"World\")"
   ]
  },
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   "execution_count": null,
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    "collapsed": true
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