{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {
    "deletable": true,
    "editable": true
   },
   "source": [
    "Playing around with various ways of doing a function\n",
    "for someone's add-on for [anki](https://en.wikipedia.org/wiki/Anki_(software%29)\n",
    "flash card stuff."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "s = 'examples/animals/mammals'\n",
    "s.count('/')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    output_terms = []\n",
    "    for term in terms:\n",
    "        output_terms.append(term)\n",
    "        yield delimiter.join(output_terms)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "examples\n",
      "examples/animals\n",
      "examples/animals/mammals\n"
     ]
    }
   ],
   "source": [
    "for t in foo(s):\n",
    "    print(t)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "known_good_output = list(foo(s))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true
   },
   "outputs": [],
   "source": [
    "# I like this version best.\n",
    "\n",
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    for i in range(len(terms)):\n",
    "        yield delimiter.join(terms[:i+1])\n",
    "\n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true
   },
   "outputs": [],
   "source": [
    "# This reduces the body to one statement,\n",
    "# but the duplication of s.split(delimiter) is ugly,\n",
    "# so I do not like this version.\n",
    "\n",
    "def foo(s, delimiter='/'):\n",
    "    yield from (\n",
    "        delimiter.join(s.split(delimiter)[:i+1])\n",
    "        for i in range(len(s.split(delimiter)))\n",
    "    )\n",
    "\n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true
   },
   "outputs": [],
   "source": [
    "# Using terms is less ugly.\n",
    "\n",
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    yield from (\n",
    "        delimiter.join(terms[:i+1])\n",
    "        for i in range(len(terms))\n",
    "    )\n",
    "\n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true
   },
   "outputs": [],
   "source": [
    "# Strictly speaking, this is a regular function\n",
    "# that returns a generator expression.\n",
    "# The duplication of s.split(delimiter) is ugly.\n",
    "\n",
    "def foo(s, delimiter='/'):\n",
    "    return (\n",
    "        delimiter.join(s.split(delimiter)[:i+1])\n",
    "        for i in range(len(s.split(delimiter)))\n",
    "    )\n",
    "\n",
    "\n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    return (delimiter.join(terms[:i+1])\n",
    "        for i in range(len(terms)))\n",
    "\n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "from itertools import accumulate"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['examples', 'examplesanimals', 'examplesanimalsmammals']"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "# Now for a functional approach.\n",
    "\n",
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    for x in accumulate(terms, str.__add__):\n",
    "        yield x\n",
    "\n",
    "list(foo(s))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    for x in accumulate(terms, lambda x, y: delimiter.join((x, y))):\n",
    "        yield x\n",
    "    \n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    yield from (\n",
    "        x\n",
    "        for x in accumulate(terms, lambda x, y: delimiter.join((x, y)))\n",
    "    )\n",
    "    \n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    terms = s.split(delimiter)\n",
    "    yield from accumulate(terms, lambda x, y: delimiter.join((x, y)))\n",
    "    \n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    yield from accumulate(\n",
    "        s.split(delimiter),\n",
    "        lambda x, y: delimiter.join((x, y))\n",
    "    )\n",
    "    \n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    return accumulate(\n",
    "        s.split(delimiter),\n",
    "        lambda x, y: delimiter.join((x, y))\n",
    "    )\n",
    "    \n",
    "assert list(foo(s)) == known_good_output"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "collapsed": false,
    "deletable": true,
    "editable": true,
    "scrolled": true
   },
   "outputs": [],
   "source": [
    "def foo(s, delimiter='/'):\n",
    "    return accumulate(\n",
    "        s.split(delimiter),\n",
    "        lambda x, y: x + delimiter + y\n",
    "    )\n",
    "    \n",
    "assert list(foo(s)) == known_good_output"
   ]
  }
 ],
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