Counter_vs_reduce_vs_sum.py

import time                                                                                                                                                                                                                                        
from collections import Counter                                                                                                                                                                                                                    
                                                                                                                                                                                                                                                   
                                                                                                                                                                                                                                                   
def fCounter(dictList):                                                                                                                                                                                                                            
    c = Counter()                                                                                                                                                                                                                                  
    t1 = time.time()                                                                                                                                                                                                                               
    for d in dictList:                                                                                                                                                                                                                             
        c.update(d)                                                                                                                                                                                                                                
    return c, time.time() - t1                                                                                                                                                                                                                     
                                                                                                                                                                                                                                                   
                                                                                                                                                                                                                                                   
def fReduce(dictList):                                                                                                                                                                                                                             
    t1 = time.time()                                                                                                                                                                                                                               
    return reduce(                                                                                                                                                                                                                                 
        lambda x, y: {                                                                                                                                                                                                                             
            k: x[k] + y[k]                                                                                                                                                                                                                         
            for k in dictList[0].iterkeys()                                                                                                                                                                                                        
        },                                                                                                                                                                                                                                         
        dictList                                                                                                                                                                                                                                   
    ), time.time() - t1                                                                                                                                                                                                                            
                                                                                                                                                                                                                                                   
                                                                                                                                                                                                                                                   
def fSum(dictList):                                                                                                                                                                                                                                
    t1 = time.time()                                                                                                                                                                                                                               
    return (                                                                                                                                                                                                                                       
        {k: sum(d[k] for d in dictList) for k in dictList[0]}, time.time() - t1                                                                                                                                                                    
    )                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                   
                                                                                                                                                                                                                                                   
def test(dictList, num=1000):                                                                                                                                                                                                                      
    tc = 0                                                                                                                                                                                                                                         
    tr = 0                                                                                                                                                                                                                                         
    ts = 0                                                                                                                                                                                                                                         
    for i in xrange(num):
        tc += fCounter(dictList)[1]                                                                                                                                                                                                                
        tr += fReduce(dictList)[1]                                                                                                                                                                                                                 
        ts += fSum(dictList)[1]                                                                                                                                                                                                                    
    return {'counter': tc / num, 'reduce': tr / num, 'sum': ts / num}

if __name__ == '__main__':
    dictList = [{'a': x, 'b': 2*x, 'c': x**2} for x in xrange(10000)]
    return test(dictList)