▍1、字母异位词
两个单词如果包含相同的字母，次序不同，则称为字母易位词(anagram)。
例如，“silent”和“listen”是字母易位词，而“apple”和“aplee”不是易位词。
from collections import Counter
s1 = 'below'
s2 = 'elbow'
print('anagram') if Counter(s1) == Counter(s2) else print('not an anagram')
使用一行Python代码，就能判断出来了。
▍2、二进制转十进制
decimal = int('1010', 2)
print(decimal) #10
▍3、将字符串转换为小写
print("Hi my name is XiaoF".lower())
# 'hi my name is xiaof'
print("Hi my name is XiaoF".casefold())
# 'hi my name is xiaof'
▍4、将字符串转换为大写
print("hi my name is XiaoF".upper())
# 'HI MY NAME IS XIAOF'
▍5、将字符串转换为字节
print("convert string to bytes using encode method".encode())
# b'convert string to bytes using encode method'
▍6、拷贝文件
import shutil
shutil.copyfile('source.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]]) print(qsort([17, 29, 11, 97, 103, 5])) # [5, 11, 17, 29, 97, 103]
▍8、n个连续数的和
n = 10 print(sum(range(0, n+1))) # 55
▍9、交换两个变量的值
a,b = b,a
▍10、斐波纳契数列
fib = lambda x: x if x<=1 else fib(x-1) + fib(x-2) print(fib(20)) # 6765
▍11、将嵌套列表合并为一个列表
main_list = [[0, 1, 2], [11, 12, 13], [52, 53, 54]] result = [item for sublist in main_list for item in sublist] print(result) > [0, 1, 2, 11, 12, 13, 52, 53, 54]
▍12、运行一个HTTP服务器
python3 -m http.server 8000 python2 -m SimpleHTTPServer
▍13、反转列表
numbers = [0, 1, 2, 11, 12, 13, 52, 53, 54] print(numbers[::-1]) # [54, 53, 52, 13, 12, 11, 2, 1, 0]
▍14、阶乘
import math fact_5 = math.factorial(5) print(fact_5) # 120
▍15、在列表推导式中使用for和if
even_list = [number for number in [1, 2, 3, 4] if number % 2 == 0] print(even_list) # [2, 4]
▍16、列表中最长的字符串
words = ['This', 'is', 'a', 'list', 'of', 'words'] result = max(words, key=len) print(result) # 'words'
▍17、列表推导式
li = [num for num in range(0, 10)] print(li) # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
▍18、集合推导式
num_set = {num for num in range(0, 10)}
print(num_set)
# {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
▍19、字典推导式
dict_numbers = {x: x*x for x in range(1, 5)}
print(dict_numbers)
# {1: 1, 2: 4, 3: 9, 4: 16}
▍20、if-else
print("even") if 4 % 2==0 else print("odd")
▍21、无限循环
while 1:0
▍22、检查数据类型
print(isinstance(2, int))
# True
print(isinstance("allwin", str))
# True
print(isinstance([3, 4, 1997], list))
# True
▍23、While循环
a = 5
while a > 0:
a = a - 1
print(a)
# 0
▍24、使用print语句写入文件
print("Hello, World!", file=open('file.txt', 'w'))
既可打印出信息，还能将信息保存文件。
▍25、计算一个字符在字符串中出现的频率
print("umbrella".count('l'))
# 2
▍26、合并列表
list1 = [1, 2, 4] list2 = ['XiaoF'] list1.extend(list2) print(list1) # [1, 2, 4, 'XiaoF']
▍27、合并字典
dict1 = {'name': 'weiwei', 'age': 23}
dict2 = {'city': 'Beijing'}
dict1.update(dict2)
print(dict1)
# {'name': 'weiwei', 'age': 23, 'city': 'Beijing'}
▍28、合并集合
set1 = {0, 1, 2}
set2 = {11, 12, 13}
set1.update(set2)
print(set1)
# {0, 1, 2, 11, 12, 13}
▍29、时间戳
import time print(time.time())
▍30、列表中出现次数最多的元素
test_list = [9, 4, 5, 4, 4, 5, 9, 5, 4] most_frequent_element = max(set(test_list), key=test_list.count) print(most_frequent_element) # 4
▍31、嵌套列表
numbers = [[num] for num in range(10)] print(numbers) # [[0], [1], [2], [3], [4], [5], [6], [7], [8], [9]]
▍32、八进制转十进制
print(int('30', 8))
# 24
▍33、将键值对转换为字典
result = dict(name='XiaoF', age=23)
print(result)
# {'name': 'XiaoF', 'age': 23}
▍34、求商和余数
quotient, remainder = divmod(4, 5) print(quotient, remainder) # 0 4 divmod()函数返回当参数1除以参数2时，包含商和余数的元组。
▍35、删除列表中的重复项
print(list(set([4, 4, 5, 5, 6]))) # [4, 5, 6]
▍36、按升序排序列表
print(sorted([5, 2, 9, 1])) # [1, 2, 5, 9]
▍37、按降序排序列表
print(sorted([5, 2, 9, 1], reverse=True)) # [9, 5, 2, 1]
▍38、获取小写字母表
import string print(string.ascii_lowercase) # abcdefghijklmnopqrstuvwxyz
▍39、获取大写字母表
import string print(string.ascii_uppercase) # ABCDEFGHIJKLMNOPQRSTUVWXYZ
▍40、获取0到9字符串
import string print(string.digits) # 0123456789
▍41、十六进制转十进制
print(int('da9', 16))
# 3497
▍42、日期时间
import time print(time.ctime()) # Thu Aug 13 20:00:00 2021
▍43、将列表中的字符串转换为整数
print(list(map(int, ['1', '2', '3']))) # [1, 2, 3]
▍44、用键对字典进行排序
d = {'one': 1, 'four': 4, 'eight': 8}
result = {key: d[key] for key in sorted(d.keys())}
print(result)
# {'eight': 8, 'four': 4, 'one': 1}
▍45、用键值对字典进行排序
x = {1: 2, 3: 4, 4: 3, 2: 1, 0: 0}
result = {k: v for k, v in sorted(x.items(), key=lambda item: item[1])}
print(result)
# {0: 0, 2: 1, 1: 2, 4: 3, 3: 4}
▍46、列表旋转
li = [1, 2, 3, 4, 5] # li[n:] + li[:n], 右变左 print(li[2:] + li[:2]) # [3, 4, 5, 1, 2] # li[-n:] + li[:-n], 左变右 print(li[-1:] + li[:-1]) # [5, 1, 2, 3, 4]
▍47、将字符串中的数字移除
message = ''.join(list(filter(lambda x: x.isalpha(), 'abc123def4fg56vcg2'))) print(message) # abcdeffgvcg
▍48、矩阵变换
old_list = [[1, 2, 3], [3, 4, 6], [5, 6, 7]] result = list(list(x) for x in zip(*old_list)) print(result) # [[1, 3, 5], [2, 4, 6], [3, 6, 7]]
▍49、列表过滤
result = list(filter(lambda x: x % 2 == 0, [1, 2, 3, 4, 5, 6])) print(result) # [2, 4, 6]
▍50、解包
a, *b, c = [1, 2, 3, 4, 5] print(a) # 1 print(b) # [2, 3, 4] print(c) # 5