50 个有趣的 Python 一行代码,都很实用!
▍1、字母异位词
两个单词如果包含相同的字母,次序不同,则称为字母易位词(anagram)。
例如,“silent”和“listen”是字母易位词,而“apple”和“aplee”不是易位词。
from collections import Counter
s1 = ‘below’
s2 = ‘elbow’
print(‘anagram’) if Counter(s1) == Counter(s2) else print(‘not an anagram’)
使用一行Python代码,就能判断出来了。
▍2、二进制转十进制
decimal = int(‘1010’, 2)
print(decimal) #10
▍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())
# 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([17, 29, 11, 97, 103, 5]))
# [5, 11, 17, 29, 97, 103]
▍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,b = b,a
▍10、斐波纳契数列
fib = lambda x: x if x<=1 else 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)
# 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