07_Ein-_und_Ausgabe_Loesungen.ipynb

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   "cells": [
    {
     "cell_type": "markdown",
     "metadata": {
      "slideshow": {
       "slide_type": "slide"
      }
     },
     "source": [
      "# L\u00f6sungen"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import numpy as np\n",
      "import tempfile\n",
      "\n",
      "from os.path import join\n",
      "\n",
      "temp = tempfile.gettempdir()"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "- speicher und lade die arrays foo und bar im numpy_compressed format ab"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "foo = np.random.rand(8, 8)\n",
      "bar = np.arange(256, dtype=np.uint8)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# speichern:\n",
      "np.savez_compressed(join(temp, 'compressed_numpy_file.npz'), foo=foo, bar=bar)\n",
      "\n",
      "# laden:\n",
      "data = np.load(join(temp, 'compressed_numpy_file.npz'))\n",
      "data['foo']\n",
      "data['bar']"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 3,
       "text": [
        "array([  0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12,\n",
        "        13,  14,  15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,\n",
        "        26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,  37,  38,\n",
        "        39,  40,  41,  42,  43,  44,  45,  46,  47,  48,  49,  50,  51,\n",
        "        52,  53,  54,  55,  56,  57,  58,  59,  60,  61,  62,  63,  64,\n",
        "        65,  66,  67,  68,  69,  70,  71,  72,  73,  74,  75,  76,  77,\n",
        "        78,  79,  80,  81,  82,  83,  84,  85,  86,  87,  88,  89,  90,\n",
        "        91,  92,  93,  94,  95,  96,  97,  98,  99, 100, 101, 102, 103,\n",
        "       104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116,\n",
        "       117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129,\n",
        "       130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142,\n",
        "       143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155,\n",
        "       156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168,\n",
        "       169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181,\n",
        "       182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194,\n",
        "       195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207,\n",
        "       208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220,\n",
        "       221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233,\n",
        "       234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246,\n",
        "       247, 248, 249, 250, 251, 252, 253, 254, 255], dtype=uint8)"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "- Lade die Datei 'files/testfile.bin' als memmap\n",
      "    - der Header (str) hat die Gr\u00f6\u00dfe 24\n",
      "    - die Daten liegen im Format int8 vor\n",
      "    - die Daten haben eine Form von 8 x 8"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# Datei erzeugen:\n",
      "with open(join('files', 'testfile.bin'), 'wb') as myfile:\n",
      "    header = 'dies ist der header! :-)'\n",
      "    myfile.write(header)\n",
      "    myfile.close()\n",
      "\n",
      "# memmap anlegen und Daten ablegen:\n",
      "data = np.memmap(join('files', 'testfile.bin'), offset=24, shape=(8,8), dtype=np.int8)\n",
      "data[:] = np.arange(64).reshape(8, 8)\n",
      "data"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "pyout",
       "prompt_number": 4,
       "text": [
        "memmap([[ 0,  1,  2,  3,  4,  5,  6,  7],\n",
        "       [ 8,  9, 10, 11, 12, 13, 14, 15],\n",
        "       [16, 17, 18, 19, 20, 21, 22, 23],\n",
        "       [24, 25, 26, 27, 28, 29, 30, 31],\n",
        "       [32, 33, 34, 35, 36, 37, 38, 39],\n",
        "       [40, 41, 42, 43, 44, 45, 46, 47],\n",
        "       [48, 49, 50, 51, 52, 53, 54, 55],\n",
        "       [56, 57, 58, 59, 60, 61, 62, 63]], dtype=int8)"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "# daten lesen:\n",
      "neu = np.memmap(join('files', 'testfile.bin'),\n",
      "                mode='r',\n",
      "                offset=24,\n",
      "                shape=(8, 8),\n",
      "                dtype=np.int8)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "neu"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 6
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "---\n",
      "<p align=\"center\">Tutorial: Einf\u00fchrung in NumPy von Henning Dickten und Christian Geier, PyCon.DE 2013</p>\n",
      "<p align=\"center\"><a rel=\"license\" href=\"http://creativecommons.org/licenses/by-nc-sa/3.0/deed.de\"><img alt=\"Creative Commons Lizenzvertrag\" style=\"border-width:0\" src=\"http://i.creativecommons.org/l/by-nc-sa/3.0/88x31.png\"/></a></p>\n",
      "\n",
      "<p align=\"center\">Dieses Werk bzw. Inhalt ist lizenziert unter einer <a rel=\"license\" href=\"http://creativecommons.org/licenses/by-nc-sa/3.0/deed.de\">Creative Commons Namensnennung - Nicht-kommerziell - Weitergabe unter gleichen Bedingungen 3.0 Unported Lizenz</a>.</p>\n",
      "\n"
     ]
    }
   ],
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