{
 "metadata": {
  "name": "",
  "signature": "sha256:91b230d6c40eec734e6eb9aae5b1d697914107974522d5a5815a24255f520d43"
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   "cells": [
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "# Recursive Functions\n",
      "\n",
      "- **Author:** [Chris Albon](http://www.chrisalbon.com/), [@ChrisAlbon](https://twitter.com/chrisalbon)\n",
      "- **Date:** -\n",
      "- **Repo:** [Python 3 code snippets for data science](https://github.com/chrisalbon/code_py)\n",
      "- **Note:**"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "## Simple factorial"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "print(5*4*3*2*1)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "120\n"
       ]
      }
     ],
     "prompt_number": 19
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "## Recursive function\n",
      "\n",
      "The tell-tale sign of a recursive function is a function that calls itself"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Create a function inputing n, that,\n",
      "def factorial(n):\n",
      "    # if n is less than or equal to 1,\n",
      "    if n <= 1:\n",
      "        # return n,\n",
      "        return n\n",
      "\n",
      "    # if not, return n multiplied by the output\n",
      "    # of the factorial function of one less than n\n",
      "    return n*factorial(n-1)\n",
      "\n",
      "# run the function\n",
      "factorial(5)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 31,
       "text": [
        "120"
       ]
      }
     ],
     "prompt_number": 31
    }
   ],
   "metadata": {}
  }
 ]
}