Python 语法简洁，能够用一行代码实现很多有趣的功能，现在整理 30 个常见的 Python 一行代码集合。
① 转置矩阵old_list = [[1, 2, 3], [3, 4, 6], [5, 6, 7]] list(list(x) for x in zip(*old_list)) [[1, 3, 5], [2, 4, 6], [3, 6, 7]]② 二进制转十进制
decimal = int('1010', 2)
print(decimal) #10
10
③ 字符串大写转小写
# 方法一 lower() "Hi my name is Allwin".lower() # 'hi my name is allwin' # 方法二 casefold() "Hi my name is Allwin".casefold() # 'hi my name is allwin' 'hi my name is allwin'④ 字符串小写转大写
"hi my name is Allwin".upper() # 'HI MY NAME IS ALLWIN' 'HI MY NAME IS ALLWIN'⑤ 将字符串转换为字节
"convert string to bytes using encode method".encode() # b'convert string to bytes using encode method' b'convert string to bytes using encode method'⑥ 复制文件内容
import shutil; shutil.copyfile('source.txt', 'dest.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]]) qsort([1,3,2]) [1, 2, 3]⑧ n 个连续数之和
n = 3 sum(range(0, n+1)) 6⑨ 交换两个变量
a=1 b=2 a,b = b,a⑩ 斐波那契数列
fib = lambda x: x if x<=1 else fib(x-1) + fib(x-2) fib(10) 55⑪ 将嵌套列表合并为一个列表
main_list = [[1,2],[3,4],[5,6,7]] [item for sublist in main_list for item in sublist] [1, 2, 3, 4, 5, 6, 7]⑫ 运行 HTTP 服务器
python3 -m http.server 8000⑬ 反转列表
numbers = 'I Love China' numbers[::-1] 'anihC evoL I'⑭ 返回阶乘
import math; fact_5 = math.factorial(5) fact_5 120⑮ 判断列表推导式
even_list = [number for number in [1, 2, 3, 4] if number % 2 == 0] even_list [2, 4]⑯ 取最长字符串
words = ['This', 'is', 'a', 'list', 'of', 'words'] max(words, key=len) 'words'⑰ 列表推导式
li = [num for num in range(0,100)] # this will create a list of numbers from 0 to 99⑱ 集合推导式
num_set = { num for num in range(0,100)}
# this will create a set of numbers from 0 to 99
⑲ 字典推导式
dict_numbers = {x:x*x for x in range(1,5) }
# {1: 1, 2: 4, 3: 9, 4: 16}
⑳ if-else
print("even") if 4%2==0 else print("odd")
even
㉑ 无限循环
while 1:0㉒ 检查数据类型
isinstance(2, int)
isinstance("allwin", str)
isinstance([3,4,1997], list)
㉓ while 循环
a=5 while a > 0: a = a - 1; print(a)㉔ 使用 print 语句写入到文件里
print("Hello, World!", file=open('source.txt', 'w'))
㉕ 统计字频
print("umbrella".count('l'))
2
㉖ 合并两个列表
list1.extend(list2) # contents of list 2 will be added to the list1㉗ 合并两个字典
dict1.update(dict2) # contents of dictionary 2 will be added to the dictionary 1㉘ 合并两个集合
set1.update(set2) # contents of set2 will be copied to the set1㉙ 时间戳
import time; print(time.time()) 1632146103.8406303㉚ 统计最多的元素
test_list = [9, 4, 5, 4, 4, 5, 9, 5, 4] most_frequent_element = max(set(test_list), key=test_list.count) most_frequent_element
最后，Python 代码哲学崇尚简洁，伙伴们也可以尝试把代码简化，看能不能实现想要的功能。
