yield.ipynb

{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "b\n",
      "a\n",
      "z\n"
     ]
    }
   ],
   "source": [
    "for c in 'baz':\n",
    "    print(c)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<generator object foo at 0x7f87aca43308>"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def foo(s):\n",
    "    for c in s:\n",
    "        yield c\n",
    "foo('baz')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "g = foo('baz')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "b\n",
      "a\n",
      "z\n"
     ]
    }
   ],
   "source": [
    "for c in g:\n",
    "    print(c)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "def foo(s):\n",
    "    print('entering foo')\n",
    "    for c in s:\n",
    "        print('top of foo loop')\n",
    "        yield c\n",
    "\n",
    "g = foo('baz')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "entering foo\n",
      "top of foo loop\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'b'"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "g.__next__()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "top of foo loop\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'a'"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "g.__next__()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "top of foo loop\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'z'"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "next(g)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "ename": "StopIteration",
     "evalue": "",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mStopIteration\u001b[0m                             Traceback (most recent call last)",
      "\u001b[0;32m<ipython-input-9-5f315c5de15b>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mnext\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mg\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[0;31mStopIteration\u001b[0m: "
     ]
    }
   ],
   "source": [
    "next(g)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<generator object bar at 0x7f87ac1b1728>"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def foo(s):\n",
    "    print('entering foo')\n",
    "    for c in s:\n",
    "        print('top of foo loop')\n",
    "        yield c\n",
    "        print('bottom of foo loop')\n",
    "\n",
    "def bar(s):\n",
    "    print('entering bar')\n",
    "    for c in s:\n",
    "        print('top of bar loop')\n",
    "        yield c.upper()\n",
    "        print('bottom of bar loop')\n",
    "\n",
    "f = foo('baz')\n",
    "g = bar(f)\n",
    "g"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "entering bar\n",
      "entering foo\n",
      "top of foo loop\n",
      "top of bar loop\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'B'"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "next(g)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "bottom of bar loop\n",
      "bottom of foo loop\n",
      "top of foo loop\n",
      "top of bar loop\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'A'"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "next(g)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['B', 'Z']\n"
     ]
    }
   ],
   "source": [
    "def foo(s):\n",
    "    for c in s:\n",
    "        yield c\n",
    "\n",
    "def bar(s):\n",
    "    for c in s:\n",
    "        yield c.upper()\n",
    "\n",
    "def filter_a(s):\n",
    "    for c in s:\n",
    "        if c != 'a':\n",
    "            yield c\n",
    "\n",
    "g = bar(filter_a(foo('baz')))\n",
    "\n",
    "s = list(g)\n",
    "print(s)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<generator object <genexpr> at 0x7f87ac1b1938>"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "foo = (c for c in 'baz')\n",
    "foo"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['B', 'Z']"
      ]
     },
     "execution_count": 15,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "foo = (c for c in 'baz')\n",
    "filter_a = (c for c in foo if c != 'a')\n",
    "bar = (c.upper() for c in filter_a)\n",
    "list(bar)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "entering foo\n",
      "get ready for f\n",
      "baz\n",
      "that was exciting\n",
      "leaving foo\n"
     ]
    }
   ],
   "source": [
    "from contextlib import contextmanager\n",
    "\n",
    "@contextmanager\n",
    "def foo(s):\n",
    "    print('entering foo')\n",
    "    yield s\n",
    "    print('leaving foo')\n",
    "\n",
    "with foo('baz') as f:\n",
    "    print('get ready for f')\n",
    "    print(f)\n",
    "    print('that was exciting')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "here comes f\n",
      "baz\n",
      "there it went\n"
     ]
    }
   ],
   "source": [
    "class CM(object):\n",
    "    def __init__(self, s):\n",
    "        self.s = s\n",
    "    def __enter__(self):\n",
    "        return self.s\n",
    "    def __exit__(self, exc, val, tb):\n",
    "        return True\n",
    "\n",
    "with CM('baz') as f:\n",
    "    print('here comes f')\n",
    "    print(f)\n",
    "    print('there it went')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'baz'"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def foo(s):\n",
    "    yield s\n",
    "\n",
    "g = foo('baz')\n",
    "result = next(g)\n",
    "result"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "entering context\n",
      "entering foo\n",
      "here comes f\n",
      "baz\n",
      "there went f\n",
      "leaving context\n"
     ]
    }
   ],
   "source": [
    "class CM(object):\n",
    "    def __init__(self, gen):\n",
    "        self.gen = gen\n",
    "    def __enter__(self):\n",
    "        print('entering context')\n",
    "        return next(self.gen)\n",
    "    def __exit__(self, exc, val, tb):\n",
    "        print('leaving context')\n",
    "        return True\n",
    "\n",
    "def foo(s):\n",
    "    print('entering foo')\n",
    "    yield s\n",
    "    print('leaving foo')\n",
    "\n",
    "with CM(foo('baz')) as f:\n",
    "    print('here comes f')\n",
    "    print(f)\n",
    "    print('there went f')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<generator object foo at 0x7f87ac1b1780>"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def foo():\n",
    "    while True:\n",
    "        s = yield\n",
    "        print(s)\n",
    "\n",
    "g = foo()\n",
    "g"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "next(g)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "None\n"
     ]
    }
   ],
   "source": [
    "next(g)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "baz\n"
     ]
    }
   ],
   "source": [
    "g.send('baz')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "def foo():\n",
    "    print('entering foo')\n",
    "    while True:\n",
    "        print('top of foo loop')\n",
    "        s = yield\n",
    "        print(s)\n",
    "        print('bottom of foo loop')\n",
    "\n",
    "    \n",
    "g = foo()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "entering foo\n",
      "top of foo loop\n"
     ]
    }
   ],
   "source": [
    "next(g)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "baz\n",
      "bottom of foo loop\n",
      "top of foo loop\n"
     ]
    }
   ],
   "source": [
    "g.send('baz')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "quux\n",
      "bottom of foo loop\n",
      "top of foo loop\n"
     ]
    }
   ],
   "source": [
    "g.send('quux')"
   ]
  }
 ],
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   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
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