python 常用代码

Python是一种高级编程语言，具有简单易学、代码简洁、可读性强等特点。以下是Python常用的一些代码：

1. 判断列表中是否有重复元素

   def all_unique(lst):
       return len(lst) == len(set(lst))

   x = [1, 1, 2, 2, 3, 2, 3, 4, 5, 6]
   y = [1, 2, 3, 4, 5]
   all_unique(x) # False
   all_unique(y) # True

2. 判断两个字符串是否由相同的字符组成

   from collections import Counter

   def anagram(first, second):
       return Counter(first) == Counter(second)

   anagram("abcd3", "3acdb") # True

3. 获取变量占用的内存大小

   import sys

   variable = 30
   print(sys.getsizeof(variable)) # 24

4. 获取字符串占用的字节数

   def byte_size(string):
       return len(string.encode('utf-8'))

   byte_size('') # 4
   byte_size('Hello World') # 11

5. 打印N次字符串

   n = 2
   s = "Programming"
   print(s * n) # ProgrammingProgramming

6. 将字符串的第一个字母大写

   s = "programming is awesome"
   print(s.title()) # Programming Is Awesome

7. 将列表分块

   from math import ceil

   def chunk(lst, size):
       return list(map(lambda x: lst[x * size:x * size + size], list(range(0, ceil(len(lst) / size)))))

   chunk([1, 2, 3, 4, 5], 2) # [[1,2],[3,4],5]

8. 统计字符串中元音字母的个数

   import re

   def count_vowels(str):
       return len(re.findall(r'[aeiou]', str, re.IGNORECASE))

   count_vowels('foobar') # 3
   count_vowels('gym') # 0

9. 将字符串的第一个字母小写

   def decapitalize(string):
       return string[:1].lower() + string[1:]

   decapitalize('FooBar') # 'fooBar'
   decapitalize('FooBar') # 'fooBar'

10. 展开列表

    def flatten(lst):
        return [item for sublist in lst for item in sublist]

    flatten([[1, 2], [3, 4]]) # [1, 2, 3, 4]