{ "metadata": { "name": "object" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "code", "collapsed": false, "input": [ "import numpy as np\n", "\n", "#from start import *\n", "\n", "# assorted data types:" ], "language": "python", "metadata": {}, "outputs": [], "prompt_number": 1 }, { "cell_type": "code", "collapsed": false, "input": [ "# usually defaults to float(64 bit)\n", "a = np.ones(3)\n", "print a.dtype" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "float64\n" ] } ], "prompt_number": 2 }, { "cell_type": "code", "collapsed": false, "input": [ "# smart enough to match input:\n", "a = np.array((3,5,7,8))\n", "print a.dtype" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "int32\n" ] } ], "prompt_number": 3 }, { "cell_type": "code", "collapsed": false, "input": [ "# smart enough to match input:\n", "a = np.array((3.0,5,7,8))\n", "print a.dtype" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "float64\n" ] } ], "prompt_number": 4 }, { "cell_type": "code", "collapsed": false, "input": [ "# or you can specify:\n", "a = np.array( (1,2,3), dtype=np.uint8 )\n", "print a.dtype" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "uint8\n" ] } ], "prompt_number": 5 }, { "cell_type": "code", "collapsed": false, "input": [ "#careful: integers overflow:\n", "a = np.array( (1, 10, 100,), dtype=np.uint8)\n", "\n", "print a\n", "\n", "a *= 3\n", "\n", "print a" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "[ 1 10 100]\n", "[ 3 30 44]\n" ] } ], "prompt_number": 6 }, { "cell_type": "code", "collapsed": false, "input": [ "# Object arrays:\n", "\n", "# create an empty array:\n", "\n", "a = np.empty((2,3), dtype=np.object)\n", "\n", "print a" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "[[None None None]\n", " [None None None]]\n" ] } ], "prompt_number": 7 }, { "cell_type": "code", "collapsed": false, "input": [ "# put stuff into it:\n", "\n", "a[0,0] = \"a string\"\n", "a[0,1] = 4.5\n", "a[0,2] = (1,2,3)\n", "a[1,:] = [6, {'a':3}, 3.4]\n", "\n", "print a" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "[[a string 4.5 (1, 2, 3)]\n", " [6 {'a': 3} 3.4]]\n" ] } ], "prompt_number": 8 }, { "cell_type": "code", "collapsed": false, "input": [ "# a row:\n", "print a[1,:]" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "[6 {'a': 3} 3.4]\n" ] } ], "prompt_number": 9 }, { "cell_type": "code", "collapsed": false, "input": [ "# a column:\n", "print a[:,1]" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "[4.5 {'a': 3}]\n" ] } ], "prompt_number": 10 }, { "cell_type": "code", "collapsed": false, "input": [ "# an item (a dict in this case)\n", "print a[1,1]" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "{'a': 3}\n" ] } ], "prompt_number": 11 }, { "cell_type": "code", "collapsed": false, "input": [ "print a[1,1]['a']" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "3\n" ] } ], "prompt_number": 12 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [], "prompt_number": 12 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [] } ], "metadata": {} } ] }