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POBest way to turn a list into a dict, where the keys are a value of each object?
 

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  1. POBest way to turn a list into a dict, where the keys are a value of each object?
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    <p>I am attempting to take a list of objects, and turn that list into a dict. The dict values would be each object in the list, and the dict keys would be a value found in each object.</p> <p>Here is some code representing what im doing:</p> <pre><code>class SomeClass(object): def __init__(self, name): self.name = name object_list = [ SomeClass(name='a'), SomeClass(name='b'), SomeClass(name='c'), SomeClass(name='d'), SomeClass(name='e'), ] object_dict = {} for an_object in object_list: object_dict[an_object.name] = an_object </code></pre> <p>Now that code works, but its a bit ugly, and a bit slow. Could anyone give an example of something thats faster/"better"?</p> <p><em>edit:</em> Alright, thanks for the replies. I must say i am surprised to see the more pythonic ways <strong>seeming</strong> slower than the hand made way.</p> <p><em>edit2:</em> Alright, i updated the test code to make it a bit more readable, with so many tests heh.</p> <p>Here is where we are at in terms of code, i put authors in the code and if i messed any up please let me know.</p> <pre><code>from itertools import izip import timeit class SomeClass(object): def __init__(self, name): self.name = name object_list = [] for i in range(5): object_list.append(SomeClass(name=i)) def example_1(): 'Original Code' object_dict = {} for an_object in object_list: object_dict[an_object.name] = an_object def example_2(): 'Provided by hyperboreean' d = dict(zip([o.name for o in object_list], object_list)) def example_3(): 'Provided by Jason Baker' d = dict([(an_object.name, an_object) for an_object in object_list]) def example_4(): "Added izip to hyperboreean's code, suggested by Chris Cameron" d = dict(izip([o.name for o in object_list], object_list)) def example_5(): 'zip, improved by John Fouhy' d = dict(zip((o.name for o in object_list), object_list)) def example_6(): 'izip, improved by John Fouhy' d = dict(izip((o.name for o in object_list), object_list)) def example_7(): 'Provided by Jason Baker, removed brackets by John Fouhy' d = dict((an_object.name, an_object) for an_object in object_list) timeits = [] for example_index in range(1, 8): timeits.append( timeit.Timer( 'example_%s()' % example_index, 'from __main__ import example_%s' % example_index) ) for i in range(7): timeit_object = timeits[i] print 'Example #%s Result: "%s"' % (i+1, timeit_object.repeat(2)) </code></pre> <p>With 5 objects in the list i am getting a result of:</p> <pre><code> Example #1 Result: "[1.2428441047668457, 1.2431108951568604]" Example #2 Result: "[3.3567759990692139, 3.3188660144805908]" Example #3 Result: "[2.8346641063690186, 2.8344728946685791]" Example #4 Result: "[3.0710639953613281, 3.0573830604553223]" Example #5 Result: "[5.2079918384552002, 5.2170760631561279]" Example #6 Result: "[3.240635871887207, 3.2402129173278809]" Example #7 Result: "[3.0856869220733643, 3.0688989162445068]" </code></pre> <p>and with 50:</p> <pre><code> Example #1 Result: "[9.8108220100402832, 9.9066231250762939]" Example #2 Result: "[16.365023136138916, 16.213981151580811]" Example #3 Result: "[15.77024507522583, 15.771029949188232]" Example #4 Result: "[14.598290920257568, 14.591825008392334]" Example #5 Result: "[20.644147872924805, 20.64064884185791]" Example #6 Result: "[15.210831165313721, 15.212569952011108]" Example #7 Result: "[17.317100048065186, 17.359367847442627]" </code></pre> <p>And lastly, with 500 objects:</p> <pre><code> Example #1 Result: "[96.682723999023438, 96.678673028945923]" Example #2 Result: "[137.49416589736938, 137.48705387115479]" Example #3 Result: "[136.58069896697998, 136.5823769569397]" Example #4 Result: "[115.0344090461731, 115.1088011264801]" Example #5 Result: "[165.08325910568237, 165.06769108772278]" Example #6 Result: "[128.95187497138977, 128.96077489852905]" Example #7 Result: "[155.70515990257263, 155.74126601219177]" </code></pre> <p>Thanks to all that replied! Im very surprised with the result. If there are any other tips for a faster method i would love to hear them. Thanks all!</p>
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    1. COYou should also check out the suggestions here, they're very similar: http://stackoverflow.com/questions/753986/is-there-a-more-pythonic-way-to-build-this-dictionary/754154#754154
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