python-optimization-peephole.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### pre-calculate"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "def consts():\n",
    "    a = 24 * 60  # constant\n",
    "    b = (1, 2, 3) * 3  # tuple are constant\n",
    "    c = 'abc'* 3  # length < 20\n",
    "    d = 'overflow' * 10  # length >= 20\n",
    "    e = [1, 2, 3] * 3  # list are not constant"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(None,\n",
       " 24,\n",
       " 60,\n",
       " 1,\n",
       " 2,\n",
       " 3,\n",
       " 'abc',\n",
       " 'overflow',\n",
       " 10,\n",
       " 1440,\n",
       " (1, 2, 3),\n",
       " (1, 2, 3, 1, 2, 3, 1, 2, 3),\n",
       " 'abcabcabc')"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "consts.__code__.co_consts"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### sequence membership"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(None, 1, 2, 3, 4, 5, (1, 2, 3, 4, 5))"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def const_list_lookup(e):\n",
    "    return e in [1, 2, 3, 4, 5]\n",
    "const_list_lookup.__code__.co_consts"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(None,\n",
       " <code object <listcomp> at 0x7f8e3936a420, file \"<ipython-input-2-44d86508875c>\", line 2>,\n",
       " 'non_const_seq_lookup.<locals>.<listcomp>',\n",
       " 100)"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def non_const_list_lookup(e):\n",
    "    return e in [i for i in range(100)]\n",
    "non_const_list_lookup.__code__.co_consts"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(None, 1, 2, 3, 4, 5, frozenset({1, 2, 3, 4, 5}))"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def const_dict_lookup(e):\n",
    "    return e in {1, 2, 3, 4, 5}\n",
    "const_dict_lookup.__code__.co_consts"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### list, tuple, set lookup comparison"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [],
   "source": [
    "import time\n",
    "import random"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [],
   "source": [
    "def membership_test(e, seq):\n",
    "    for i in range(1000000):\n",
    "        if e in seq:\n",
    "            pass"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "list lookup took: 7.701791076000063\n"
     ]
    }
   ],
   "source": [
    "start = time.perf_counter()\n",
    "\n",
    "lst = [int(1000*random.random()) for i in range(10000)]\n",
    "membership_test(55, lst)\n",
    "\n",
    "end = time.perf_counter()\n",
    "\n",
    "print('list lookup took:', end - start)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "tuple lookup took: 7.798407105000024\n"
     ]
    }
   ],
   "source": [
    "start = time.perf_counter()\n",
    "\n",
    "tpl = (int(1000*random.random()) for i in range(10000))\n",
    "membership_test(55, lst)\n",
    "\n",
    "end = time.perf_counter()\n",
    "\n",
    "print('tuple lookup took:', end - start)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "set lookup took: 0.06725922400028139\n"
     ]
    }
   ],
   "source": [
    "start = time.perf_counter()\n",
    "\n",
    "st = {int(1000*random.random()) for i in range(10000)}\n",
    "membership_test(55, st)\n",
    "\n",
    "end = time.perf_counter()\n",
    "\n",
    "print('set lookup took:', end - start)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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