{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The string [join method](https://docs.python.org/3/library/stdtypes.html#str.join)\n",
    "can concatenate strings significantly faster than using the '+' operator.\n",
    "I think Raymond Hettinger talked about this in one of his presentations\n",
    "archived on pyvideo.org."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "width = 1000"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def foo(width):\n",
    "    horizontal_line = '{'\n",
    "    for i in range(width):\n",
    "        horizontal_line += (' ' + '#ffffff')\n",
    "    horizontal_line += '}'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1000 loops, best of 3: 210 µs per loop\n"
     ]
    }
   ],
   "source": [
    "%timeit foo(width)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def foo(width):\n",
    "    horizontal_line = (\n",
    "        '{' +\n",
    "        ' '.join(\n",
    "            '#ffffff' for i in range(width)\n",
    "        ) +\n",
    "        '}'\n",
    "    )"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "10000 loops, best of 3: 129 µs per loop\n"
     ]
    }
   ],
   "source": [
    "%timeit foo(width)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "def foo(width):\n",
    "    horizontal_line = ''.join([\n",
    "        '{',\n",
    "        ' '.join(\n",
    "            '#ffffff' for i in range(width)\n",
    "        ),\n",
    "        '}',\n",
    "    ])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "10000 loops, best of 3: 129 µs per loop\n"
     ]
    }
   ],
   "source": [
    "%timeit foo(width)"
   ]
  }
 ],
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