程序员必备的Python技巧和窍门？
在本文中，我们将介绍一些有用的python技巧和窍门，当您在竞争性编程中编写程序时或在您的公司中使用它们时，它们将减少代码并优化执行，因此非常有用。
就地交换两个数字
x, y = 50, 70 print(x, y) #swapping x, y = y, x print(x, y)
输出结果
50 70 70 50
从列表创建单个字符串
lst = ['What', 'a', 'fine', 'morning']
print(" ".join(lst))输出结果
What a fine morning
从列表中删除重复项
# Remove duplicates from a list
#This method will not preserve the order
lst = [2, 4, 4 ,9 , 13, 4, 2]
print("Original list: ", lst)
new_lst = list(set(lst))
print(new_lst)
# Below method will preserve the order
from collections import OrderedDict
lst = [2, 4, 4 ,9 , 13, 4, 2]
print(list(OrderedDict.fromkeys(lst).keys()))输出结果
Original list: [2, 4, 4, 9, 13, 4, 2] [9, 2, 4, 13] [2, 4, 9, 13]
反转字符串
#Reverse a string
s = "Hello, World!"
print(s[::-1])
letters = ("abcdefghijklmnopqrstuvwxyz")
print(letters[::-1])输出结果
!dlroW ,olleH Zyxwvutsrqponmlkjihgfedcba
倒转列表
# Reversing a list lst = [20, 40 , 60, 80] print(lst[::-1])
输出结果
[80, 60, 40, 20]
转置二维数组
#Transpose of a 2d array, that means if the matrix is 2 * 3 after transpose it will be 3* 2 matrix. matrix = [['a', 'b', 'c'], ['d', 'e', 'f']] transMatrix = zip (*matrix) print(list (transMatrix))
输出结果
[('a', 'd'), ('b', 'e'), ('c', 'f')]检查两个字符串是否是字谜
#Check if two strings are anagrams
from collections import Counter
def is_anagram (str1, str2):
return Counter(str1) == Counter(str2)
print(is_anagram('hello', 'ollhe'))
#and
print(is_anagram('Hello', 'hello'))输出结果
True False
在python中检查对象
#Inspect an object in pyton lst =[1, 3, 4, 7, 9] print(dir(lst))
输出结果
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']
列举列表
#Enumerate a list lst = [20, 10, 40, 50 , 30, 40] for i, value in enumerate(lst): print(i, ': ', value)
输出结果
0 : 20 1 : 10 2 : 40 3 : 50 4 : 30 5 : 40
任何数量的阶乘
#Factorial of any number import functools result = (lambda s: functools.reduce(int. __mul__, range(1, s+1), 1))(5) print(result)
输出结果
120
根据两个相关序列创建字典
#Creating a dictionary from two related sequences
x1 = ('Name', 'EmpId', 'Sector')
y1 = ('Zack', 4005, 'Finance')
print(dict (zip(x1, y1)))输出结果
{'Name': 'Zack', 'EmpId': 4005, 'Sector': 'Finance'}