25条很棒的Python一行代码
▍1、交换两个变量
# a = 4 b = 5 a,b = b,a # print(a,b) >> 5,4
2、多个变量赋值
a,b,c = 4,5.5,'Hello' #print(a,b,c) >> 4,5.5,hello
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
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
# Deleting all even a = [1,2,3,4,5] del a[1::2] print(a) >[1, 3, 5] a
▍5、读取文件
lst = [line.strip() for line in open('data.txt')]
print(lst)
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
with open("data.txt",'a',newline='\n') as f:
f.write("Python is awsome")
▍7、创建列表
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)
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
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
# 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
['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
text = 'level' ispalindrome = text == text[::-1] ispalindrome > True
▍12、用空格分隔的整数到一个列表
lis = list(map(int, input().split())) print
▍13、Lambda函数
# 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
num = 5
if num in [1,2,3,4,5]:
print('present')
> present
▍15、打印图案
n = 5
print('\n'.join('😀' * i for i in range(1, n + 1)))
>
😀
😀😀
😀😀😀
😀😀😀😀
😀😀😀😀😀
▍16、查找阶乘
import math n = 6 math.factorial(n) > 720
▍17、斐波纳契数列
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
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
findmax = lambda x,y: x if x > y else y findmax(5,14) > 14 or max(5,14)
▍20、线性代数
def scale(lst, x):
return [i*x for i in lst]
scale([2,3,4], 2)
> [4,6,8]
▍21、矩阵转置
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。
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
"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
import random random.choice(['Head',"Tail"]) > Head
▍25、生成组
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)]
