Generators and Recusion.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Generators"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "45"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# a generator that yields items instead of returning a list\n",
    "def firstn(n):\n",
    "    num = 0\n",
    "    while num < n:\n",
    "        yield num\n",
    "        num += 1\n",
    "        \n",
    "sum(firstn(10))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[i for i in firstn(10)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def unique(iterable, key=lambda x: x):\n",
    "    seen = set()\n",
    "    for elem, ekey in ((e, key(e)) for e in iterable):\n",
    "        if ekey not in seen:\n",
    "            yield elem\n",
    "            seen.add(ekey)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "[i for i in unique(range(10))]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "---"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "class Example(object):\n",
    "    def __init__(self):\n",
    "        self.my_string = \"hello\"\n",
    "        self.my_set = {1,2,3}\n",
    "class Example2(object):\n",
    "    def __init__(self):\n",
    "        self.my_list = [4,5,6]\n",
    "        self.my_class_instance = Example()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def inspectObject(obj):\n",
    "    \"\"\"Returns a list of object attributes and their types.\n",
    "\n",
    "    Parameters\n",
    "    ----------\n",
    "    obj: :obj:\n",
    "        Any kind of object that is not a builtin.\n",
    "\n",
    "    Returns\n",
    "    -------\n",
    "    obj_ids: list\n",
    "        A list of lists to be specific.\n",
    "    \"\"\"\n",
    "    # Make list of builtins\n",
    "    bi_list = dir(__builtins__)\n",
    "    # Try to make a list of the types of things inside obj.\n",
    "    try:\n",
    "        # Make list all things inside of an object\n",
    "        obj_ids = [[name, type(thing).__name__] for name, thing in obj.__dict__.items()]\n",
    "\n",
    "        return obj_ids\n",
    "\n",
    "    except Exception:\n",
    "        pass\n",
    "\n",
    "\n",
    "def objectWalker(obj, desired_type=None, att_list=None):\n",
    "    \"\"\"Recursively walks through an object an genrates a list of its attributes.\n",
    "\n",
    "    Parameters\n",
    "    ----------\n",
    "    obj: :obj:\n",
    "\n",
    "    desired_type: str\n",
    "\n",
    "    Returns\n",
    "    -------\n",
    "    att_list: list\n",
    "\n",
    "    \"\"\"\n",
    "    # Create an attributes list if none has been asigned.\n",
    "    if att_list is None:\n",
    "        att_list = []\n",
    "\n",
    "    # Create list of types that we do not want yo serch through\n",
    "    no_list = dir(__builtins__)\n",
    "    no_list.append(\"DataFrame\")\n",
    "    # desired_type = desired_type or \"DataFrame\"\n",
    "\n",
    "    obj_inspect = inspectObject(obj)\n",
    "\n",
    "    for i in obj_inspect:\n",
    "\n",
    "        # Test if object attribute is desired_type.\n",
    "        if re.search(desired_type, i[1], re.I) is not None:\n",
    "\n",
    "            att_list.append(i)\n",
    "\n",
    "        # If the object attribute is not the desired_type then...\n",
    "        elif i[1] not in no_list:\n",
    "            # Try to use recursively objectWalker on the object.\n",
    "            try:\n",
    "                objectWalker(obj.__dict__[i[0]], desired_type, att_list)\n",
    "            except:\n",
    "                pass\n",
    "    return att_list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "ex = Example2()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[['my_set', 'set']]"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "objectWalker(ex,\"set\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[['my_string', 'str']]"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "objectWalker(ex,\"str\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[['my_class_instance', 'Example']]"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "objectWalker(ex,\"Example\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "anaconda-cloud": {},
  "kernelspec": {
   "display_name": "Python [Root]",
   "language": "python",
   "name": "Python [Root]"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.5.2"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}