python basic operation

文章目錄

• • 十進制轉二進制、八進制、十六進制
  • 二進制/八進制/十六進制 轉 十進制
  • Integer to integer list
  • Convert a list of integers to integers
  • 與、非、或、異或、位移
  • 將asciiThe code is converted to the corresponding letter
  • convert letters toascii碼
  • 枚舉 enumerate

十進制轉二進制、八進制、十六進制

bin(5) # '0b101'
oct(5) # '0o5'
hex(5) # '0x5'

二進制/八進制/十六進制 轉 十進制

int('110',2) # 6
int('110',8) # 64+8=72
int('110', 16) # 16*16+16=272 

Integer to integer list

eg. 123 => [1, 2, 3]

a = 123
b = str(a) #'123'
c = list(b) #['1','2','3']
d = list(map(int,c)) #[1, 2, 3]

Convert a list of integers to integers

eg. [1,2,3] => 123

a = [1,2,3]
b = list(map(str,a)) # ['1', '2', '3']
c = ''.join(b) # '123'
d = int(c) # 123

與、非、或、異或、位移

與非或異或左移右移&~|^<<;相當於乘2^k>>;相當於整除2^k5&3=1
(101) | (011) = (001)~5=6
見下面的解釋5|3=7
(101) | (011) = (111)5^3=6
(101) | (011) = (110)5<<2 = 205>>1 = 2

In the computer, the calculation is performed in the form of two's complement,5的是正數,補碼等於原碼：0000 0000 0000 0000 0000 0000 0000 0101, 取非後：1111 1111 1111 1111 1111 1111 1111 1010, Computer operations are performed in two's complement form,However, it is still displayed in the original form on the terminal,Convert the result back to the original code（補碼的補碼,Complementing a negative number is adding the inverse1）：1000 0000 0000 0000 0000 0000 0000 0110, 也就是-6.

將asciiThe code is converted to the corresponding letter

chr(97) #'a'

convert letters toascii碼

ord('a') # 97

枚舉 enumerate

numbers=[0,0,3,4]
for i,num in enumerate(numbers):
print(i, num)

0 0
1 0
2 3
3 4

分別是index, 和值