50条有趣的python一行代码！
1.字母异位词
from collections import Counter
# Counter: Elements are stored as dictionary keys and their counts are stored as dictionary values.
s1 = 'below'
s2 = 'elbow'
print(Counter(s1)) # Counter({'b': 1, 'e': 1, 'l': 1, 'o': 1, 'w': 1})
print('anagram') if Counter(s1) == Counter(s2) else print('not an anagram')
2.二进制转十进制
decimal = int("1010", 2)
print(decimal)
3.将字符串转换为小写
print("Hi my name is XiaoF".lower())
# 'hi my name is xiaof'
print("Hi my name is XiaoF".casefold())
# 'hi my name is xiaof'
4.将字符串转换为大写
print("hi my name is XiaoF".upper())
# 'HI MY NAME IS XIAOF'
5.将字符串转换为字节
print("convert string to bytes using encode method".encode())
print(type("convert string to bytes using encode method".encode()))
b'convert string to bytes using encode method'
6.拷贝文件
import shutil
shutil.copyfile('source.txt', 'dest.txt')
7.快速排序
qsort = lambda l: l if len(l) <= 1 else qsort([x for x in l[1:] if x < l[0]]) + [l[0]] + qsort([x for x in l[1:] if x >= l[0]])
print(qsort([1]))
print(qsort([17, 29, 11, 97, 103, 5]))
8.n个连续数的和
n = 10
print(sum(range(0, n+1)))
# 55
9.交换两个变量的值
a = 1
b = 2
print(a, b)
a,b = b,a
print(a, b)
10.斐波纳契数列
fib = lambda x: x if x<=1 else fib(x-1) + fib(x-2)
def fib(x):
if x <= 1:
return x
else:
return fib(x-1) + fib(x-2)
print(fib(20))
# 6765
11.将嵌套列表合并为一个列表
main_list = [[0, 1, 2], [11, 12, 13], [52, 53, 54]]
result = [item for sublist in main_list for item in sublist]
print(result)
# [0, 1, 2, 11, 12, 13, 52, 53, 54]
12.运行一个HTTP服务器
python3 -m http.server 8000
python2 -m SimpleHTTPServer
13.反转列表
numbers = [0, 1, 2, 11, 12, 13, 52, 53, 54]
print(numbers[::-1])
# [54, 53, 52, 13, 12, 11, 2, 1, 0]
14.阶乘
import math
fact_5 = math.factorial(5)
print(fact_5)
# 120
15.在列表推导式中使用for和if
even_list = [number for number in [1, 2, 3, 4] if number % 2 == 0]
print(even_list)
# [2, 4]
16.列表中最长的字符串
words = ['This', 'is', 'a', 'list', 'of', 'words']
result = max(words, key=len)
print(result)
# 'words'
17.列表推导式
li = [num for num in range(0, 10)]
print(li)
# [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
18.集合推导式
num_set = {num for num in range(0, 10)}
print(num_set)
# {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
19.字典推导式
dict_numbers = {x: x*x for x in range(1, 5)}
print(dict_numbers)
# {1: 1, 2: 4, 3: 9, 4: 16}
20.if-else
print("even") if 4 % 2==0 else print("odd")
21.无限循环
while 1:0
22.检查数据类型
print(isinstance(2, int))
# True
print(isinstance("allwin", str))
# True
print(isinstance([3, 4, 1997], list))
# True
23.While循环
a = 5
while a > 0:
a = a - 1
print(a)
# 0
24.使用print语句写入文件
print("Hello, World!", file=open('file.txt', 'w'))
# 既可打印出信息，还能将信息保存文件。
25.计算一个字符在字符串中出现的频率
print("umbrella".count('l'))
# 2
26.合并列表
list1 = [1, 2, 4]
list2 = ['XiaoF']
list1.extend(list2)
print(list1)
# [1, 2, 4, 'XiaoF']
27.合并字典
dict1 = {'name': 'weiwei', 'age': 23}
dict2 = {'city': 'Beijing'}
dict1.update(dict2)
print(dict1)
# {'name': 'weiwei', 'age': 23, 'city': 'Beijing'}
28.合并集合
set1 = {0, 1, 2}
set2 = {11, 12, 13}
set1.update(set2)
print(set1)
# {0, 1, 2, 11, 12, 13}
29.时间戳
import time
print(time.time())
30.列表中出现次数最多的元素
test_list = [9, 4, 5, 4, 4, 5, 9, 5, 4]
most_frequent_element = max(set(test_list), key=test_list.count)
print(most_frequent_element)
# 4
31.嵌套列表
numbers = [[num] for num in range(10)]
print(numbers)
# [[0], [1], [2], [3], [4], [5], [6], [7], [8], [9]]
32.八进制转十进制
print(int('30', 8))
# 24
33.将键值对转换为字典
result = dict(name='XiaoF', age=23)
print(result)
# {'name': 'XiaoF', 'age': 23}
34.求商和余数
quotient, remainder = divmod(4, 5)
print(quotient, remainder)
# 0 4
# divmod()函数返回当参数1除以参数2时，包含商和余数的元组。
35.删除列表中的重复项
print(list(set([4, 4, 5, 5, 6])))
# [4, 5, 6]
36.按升序排序列表
print(sorted([5, 2, 9, 1]))
# [1, 2, 5, 9]
37.按降序排序列表
print(sorted([5, 2, 9, 1], reverse=True))
# [9, 5, 2, 1]
38.获取小写字母表
import string
print(string.ascii_lowercase)
print(type(string.ascii_lowercase))
# abcdefghijklmnopqrstuvwxyz
39.获取大写字母表
import string
print(string.ascii_uppercase)
# ABCDEFGHIJKLMNOPQRSTUVWXYZ
40.获取0到9字符串
import string
print(string.digits)
# 0123456789
41.十六进制转十进制
print(int('da9', 16))
# 3497
42.日期时间
import time
print(time.ctime())
# Thu Aug 13 20:00:00 2021
43.将列表中的字符串转换为整数
print(list(map(int, ['1', '2', '3'])))
# [1, 2, 3]
44.用键对字典进行排序
d = {'one': 1, 'four': 4, 'eight': 8}
result = {key: d[key] for key in sorted(d.keys())}
print(result)
# {'eight': 8, 'four': 4, 'one': 1}
45.用键值对字典进行排序
x = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}
result = {k: v for k, v in sorted(x.items(), key=lambda item: item[0])}
print(result)
# {0: 0, 2: 1, 1: 2, 4: 3, 3: 4}
46.列表旋转
li = [1, 2, 3, 4, 5]
# li[n:] + li[:n], 右变左
print(li[2:] + li[:2])
# [3, 4, 5, 1, 2]
# li[-n:] + li[:-n], 左变右
print(li[-1:] + li[:-1])
# [5, 1, 2, 3, 4]
47.将字符串中的数字移除
message = ''.join(list(filter(lambda x: x.isalpha(), 'abc123def4fg56vcg2')))
print(message)
# abcdeffgvcg
48.矩阵变换
old_list = [[1, 2, 3], [3, 4, 6], [5, 6, 7]]
result = list(list(x) for x in zip(*old_list))
print(result)
# [[1, 3, 5], [2, 4, 6], [3, 6, 7]]
49.列表过滤
result = list(filter(lambda x: x % 2 == 0, [1, 2, 3, 4, 5, 6]))
print(result)
# [2, 4, 6]
50.解包
a, *b, c = [1, 2, 3, 4, 5]
print(a) # 1
print(b) # [2, 3, 4]
print(c) # 5