25条很棒的Python一行代码

▍1、交换两个变量

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# a = 4 b = 5 a,b = b,a # print(a,b) >> 5,4

2、多个变量赋值 

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1 2	a,b,c = 4,5.5,'Hello' #print(a,b,c) >> 4,5.5,hello

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a,b,*c = [1,2,3,4,5] print(a,b,c) > 1 2 [3,4,5]

▍3、列表中偶数的和

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a = [1,2,3,4,5,6] s = sum([num for num in a if num%2 == 0]) print(s) >> 12

▍4、从列表中删除多个元素

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# Deleting all even a = [1,2,3,4,5] del a[1::2] print(a)   >[1, 3, 5]   a

▍5、读取文件

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1 2	lst = [line.strip() for line in open('data.txt')] print(lst)

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list(open('data.txt'))   ##Using with will also close the file after use with open("data.txt") as f:     lst=[line.strip() for line in f] print(lst)

▍6、将数据写入文件

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1 2	with open("data.txt",'a',newline='\n') as f:     f.write("Python is awsome")

▍7、创建列表

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lst = [i for i in range(0,10)] print(lst) > [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]   or   lst = list(range(0,10)) print(lst)

　　

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lst = [("Hello "+i) for i in ['Karl','Abhay','Zen']] print(lst) > ['Hello Karl', 'Hello Abhay', 'Hello Zen']

　▍8、映射列表或类型转换整个列表

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list(map(int,['1','2','3'])) > [1, 2, 3]   list(map(float,[1,2,3])) > [1.0, 2.0, 3.0]   [float(i) for i in [1,2,3]] > [1.0, 2.0, 3.0]

　▍9、创建集合

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# Square of all even numbers in an range {x**2 for x in range(10) if x%2==0}   > {0, 4, 16, 36, 64}

　▍10、Fizz Buzz

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['FizzBuzz' if i%3==0 and i%5==0     else 'Fizz' if i%3==0     else 'Buzz' if i%5==0     else i  for i in range(1,20)]

　▍11、回文

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text = 'level' ispalindrome = text == text[::-1] ispalindrome   > True

▍12、用空格分隔的整数到一个列表

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1 2	lis = list(map(int, input().split())) print

▍13、Lambda函数 

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# Function that returns square of any number sqr = lambda x: x * x sqr(10)   > 100

▍14、检查列表中数字的存在

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num = 5 if num in [1,2,3,4,5]:      print('present')   > present

▍15、打印图案

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n = 5   print('\n'.join('😀' * i for i in range(1, n + 1)))   > 😀 😀😀 😀😀😀 😀😀😀😀 😀😀😀😀😀

▍16、查找阶乘

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import math n = 6 math.factorial(n)   > 720

▍17、斐波纳契数列

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fibo = [0,1]   [fibo.append(fibo[-2]+fibo[-1]) for i in range(5)] fibo   > [0, 1, 1, 2, 3, 5, 8]

▍18、质数 

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list(filter(lambda x:all(x % y != 0 for y in range(2, x)), range(2, 13)))   > [2, 3, 5, 7, 11]

▍19、查找最大数值

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findmax = lambda x,y: x if x > y else y findmax(5,14)   > 14   or max(5,14)

▍20、线性代数

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def scale(lst, x):     return [i*x for i in lst]     scale([2,3,4], 2)   > [4,6,8]

▍21、矩阵转置 

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a=[[1,2,3],    [4,5,6],    [7,8,9]] transpose = [list(i) for i in zip(*a)] transpose   > [[1, 4, 7], [2, 5, 8], [3, 6, 9]]

▍22、计数

当我们需要知道某个值在文本中出现的次数时，这是一个重要而有用的用例。在Python中，有re库可以来帮你完成这项工作。

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import re   len(re.findall('python','python is a programming language. python is python.'))   > 3

▍23、用其他文本替换文本 

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"python is a programming language.python is python".replace("python",'Java')   > Java is a programming language. Java is Java

▍24、模拟抛硬币

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import random   random.choice(['Head',"Tail"])   > Head

▍25、生成组

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groups = [(a, b) for a in ['a', 'b'] for b in [1, 2, 3]] groups   > [('a', 1), ('a', 2), ('a', 3), ('b', 1), ('b', 2), ('b', 3)]