python decimal integer to hexadecimal bytes
Used in serial port sending, input decimal array, output hexadecimal
a = [1,3,4,5,6,7,8]
b = bytes(a).hex()
data = bytes.fromhex(b)
output
b'\x01\x03\x04\x05\x06\x07\x08'
1. Decimal to hexadecimal
Decimal and hexadecimal conversions use hex()and int().
>>> a = 11
>>> b = hex(a)
>>> b
'0xb'
>>> type(a)
<class 'int'>
>>> type(b)
<class 'str'>
a is an integer, converted to hexadecimal b is a string
>>> b = 0x11
>>> a = int(b)
>>> a
17
>>> type(a)
<class 'int'>
>>> type(b)
<class 'int'>
Among them, a and b are integers.
2.hex and fromhex in bytes
- hex: Convert the value of bytes to fromstr.
Input an integer array and get a hexadecimal string
>>> a = [0,1,2,3,4,5]
>>> bytes(a).hex()
'000102030405'
>>> type(bytes(a).hex())
<class 'str'> # 输出是字符串
As for why it is bytes(a).hex()written like this, I don’t understand, but I tried it.
>>> a = [1,2,3,4,5,6]
>>> b = bytes.hex(a)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: descriptor 'hex' for 'bytes' objects doesn't apply to a 'list' object # hex的参数应该是bytes，所以报错了。
>>> b = bytes(a)
>>> c = bytes.hex(b)
>>> c # 首先将数组转成bytes，然后再用这个函数，可以正常打印
'010203040506'
>>> c= hex(b) #直接用hex()函数将bytes转16进制也不行，hex()的输入必须是整数
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'bytes' object cannot be interpreted as an integer
- fromhex: Convert the value of fromstr to hex
Input a hexadecimal string and get the output of hexadecimal bytes with \x
>>> b = '000102030405'
>>> bytes.fromhex(b)
b'\x00\x01\x02\x03\x04\x05'
>>> type(b)
<class 'str'>
>>> type(bytes.fromhex(b))
<class 'bytes'> # 输出是bytes
3. supplement
- encode and decode in python
encode is encoding, decode is decoding
- encode() converts strings to bytes
- decode() decodes the bytes type into a string