python字符串过滤性能比较5种方法

python字符串过滤性能比较5种方法比较

总共比较5种方法。直接看代码：

import random
import time
import os
import string

base = string.digits+string.punctuation
total = 100000

def loop(ss):
 """循环"""
 rt = ''
 for c in ss:
   if c in '0123456789':
     rt = rt + c
 return rt

def regular(ss):
 """正则表达式"""
 import re
 rt = re.sub(r'\D', '', ss)
 return rt

def filter_mt(ss):
 """函数式"""
 return filter(lambda c:c.isdigit(), ss)

def list_com(ss):
 """列表生成式"""
 isdigit = {'0': 1, '1': 1, '2': 1, '3': 1, '4': 1,
           '5':1, '6':1, '7':1, '8':1, '9':1}.has_key
 return ''.join([x for x in ss if isdigit(x)])

def str_tran(ss):
 """string.translate()"""
 table = string.maketrans('', '')
 ss = ss.translate(table,string.punctuation)
 return ss

if __name__ == '__main__':
 lst = []
 for i in xrange(total):
   num = random.randrange(10, 50)
   ss = ''
   for j in xrange(num):
     ss = ss + random.choice(base)
   lst.append(ss)

s1 = time.time()
 map(loop,lst)
 print "loop: ",time.time() - s1
 print '*'*20
 s1 = time.time()
 map(regular, lst)
 print "regular: ", time.time() - s1
 print '*' * 20
 s1 = time.time()
 map(str_tran, lst)
 print "str_tran: ", time.time() - s1
 print '*' * 20
 s1 = time.time()
 map(filter_mt, lst)
 print "filter_mt: ", time.time() - s1
 print '*' * 20
 s1 = time.time()
 map(list_com, lst)
 print "list_com: ", time.time() - s1

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