20个值得学习的 Python 技巧

str1="qwert"rev_str1=str1[::-1] #输出  # trewq

str1="this is a book"print(str1.title()) # This Is A Book

str1="aabbccccdddd"set1=set(str1) new_str=''.join(set1) print(new_str)

i=4 str1="abcd"list1=[1,2] print(str1*i) # abcdabcdabcdabcd  print(list1*i) # [1,2,1,2,1,2,1,2]

list1=[1,2,3] new_list1=[2*i for i in list1] # [2,4,6]

x=1 y=2 x,y=y,x print(x) # 2  print(y) # 1

str1="This is a book"str2="test/ str 2"print(str1.split()) # ['This', 'is', 'a', 'book'] print(str2.split('/')) # ['test', ' str 2']

list_str=['This','is','a','book']print(','.join(list_str))# This,is,a,book

str1="qqaabb"if str1==str1[::-1]:  print("回文")else:  print("不是")  # 不是

from collections import Counterlist1=['a','b','a','c','c','c']count=Counter(list1)print(count)print(count['b'])print(count.most_common(1))

s1,s2,s3="acbde","abced","abcda"c1,c2,c3=Counter(s1),Counter(s2),Counter(s3)if c1==c2:  print('1和2是异序词') if c1==c3:   print('1和3是异序词')

a,b=1,0try:  print(a/b)  # b为0的时候触发异常except ZeroDivisionError:  print("除数为0")else:  print("不存在异常")finally:  print("此段总是会执行")

list1=['a','b','c','d','e']for idx,val in enumerate(list1):  print('{0}:{1}'.format(idx,val))# 0:a# 1:b# 2:c# 3:d# 4:e

import sysnum=21print(sys.getsizeof(num))

dic1={'app':9,'banana':6}dic2={'banana':4,'orange':8}com_dict={**dic1,**dic2}# {'apple':9,'banana':4,'orange':8}

import times_time=time.time()a,b=1,2c=a+b e_time=time.time()time_taken_in_micro=(e_time-stime)*(10**6)print("程序运行的毫秒：{0} ms".format(time_taken_in_micro)) 

from iteration_utilities import deepflatten# 如果嵌套列表的深度只有1层def flatten(l):  return [item for sublist in l for item in sublist]l=[[1,2,3],[3]]print(flatten(l))# [1,2,3,3]
# 如果不知道列表嵌套深度l=[[1,2,3],[4,[5],[6,7]],[8,[9,[10]]]]print(list(deepflatten(l,depth=3)))# [1,2,3,4,5,6,7,8,9,10]

import randomlist1=['a','b','c','d','e']ns=2samples=random.sample(list1,ns)print(samples)# ['a','c']

import secretss_rand=secrets.SystemRanom()list1=['a','b','c','d','e']ns=2samples=s_rand.sample(list1,ns)print(samples)# ['c','d']

nums=123456# 使用mapdigit_list=list(map(int,str(nums)))print(digit_list)# [1,2,3,4,5,6]# 使用列表表达式digit_list=[int(x) for x in str(nums)]print(digit_list)# [1,2,3,4,5,6]

def unique(l):  if len(l)==len(set(l)):      print("所有元素是唯一的")   else:      prin