Python Learning Notes _ Dictionary (Dict) _ Traversal _ Different Methods _ Performance test comparison

Today, the Python dictionary has been specifically tested for performance results in comparison with various methods.

The test code is as follows:

1 defdict_traverse ():2      fromTimeImportClock3My_dict = {'name':'Jim',' Age':' -','Height':'180cm','Weight':'60kg'}4 5T_start =clock ()6      forKeyinchMy_dict:#worst-performing notation. No optimization7         Print 'Type01.01:%s---%s'%(Key, My_dict[key])8T1 =clock ()9 Ten      forKeyinchMy_dict:#The performance is better, the visible get () method is optimized. One         Print 'Type01.02:%s---%s'%(Key, My_dict.get (key)) At2 =clock () -  -      forKeyinchMy_dict.keys ():#the keys () method is also optimized. the         Print 'Type02.01:%s---%s'%(Key, My_dict[key]) -T3 =clock () -  -      forKeyinchMy_dict.keys ():#  +         Print 'Type02.02:%s---%s'%(Key, My_dict.get (key)) -T4 =clock () +  A      forKey, ValueinchMy_dict.items ():#standard notation, performance best written at         Print 'Type03:%s---%s'%(key, value) -T5 =clock () -  -      forKey, ValueinchMy_dict.iteritems ():#The performance is higher, there is a small loss. -         Print 'Type04:%s---%s'%(key, value) -T6 =clock () in  -      forKey, ValueinchZip (My_dict.iterkeys (), My_dict.itervalues ()):#poor performance. to         Print 'Type05:%s---%s'%(key, value) +T7 =clock () -  the     Print '********** Time cost ******************' *     Print 'Type01.01--Total time:', t1-T_start $     Print 'Type01.02--Total time:', t2-T1Panax Notoginseng     Print 'Type02.01--Total time:', t3-T2 -     Print 'Type02.02--Total time:', t4-T3 the     Print 'TYPE03--Total time:', t5-T4 +     Print 'TYPE04--Total time:', t6-T5 A     Print 'Type05--Total time:', t7-T6 the  +  -  $ if __name__=='__main__': $Dict_traverse ()

After several runs, it can be found that different writing, time-consuming is a difference.

The comparison results are as shown.

In contrast, it can be found that:

For dictionary traversal, the following is recommended, performance is optimal.

1  for inch My_dict.items (): 2     Print

Python Learning Notes _ Dictionary (Dict) _ Traversal _ Different Methods _ Performance test comparison