我在用pySerial
读取TTL字节流。读取两个字节:
CheckSumByte = [ b for b in ser.read(2)]
print( CheckSumByte)
print( type(CheckSumByte))
print( str(len(CheckSumByte)))
print( CheckSumByte[0])
Output:
[202, 87]
<class 'list'>
2
IndexError: list index out of range
我无法访问的任何元素CheckSumByte
按索引(0 或 1)。怎么了?
这是我的代码:
while(ReadBufferCount < 1000):
time.sleep(0.00002)
InputBuffer = ser.inWaiting()
if (InputBuffer > 0):
FirstByte = ser.read(1)
if ord(FirstByte) == 0xFA:
while ser.inWaiting() < 21: pass
IndexByte = ser.read(1)
SpeedByte = [ b for b in ser.read(2)]
DataByte0 = [ b for b in ser.read(4)]
DataByte1 = [ b for b in ser.read(4)]
DataByte2 = [ b for b in ser.read(4)]
DataByte3 = [ b for b in ser.read(4)]
CheckSumByte = [ b for b in ser.read(2)]
print( CheckSumByte[0]) #Out of Range??`
Traceback (most recent call last):
File "<ipython-input-6-5233b0a578b1>", line 1, in <module>
runfile('C:/Users/Blair/Documents/Python/Neato XV-11 Lidar/Serial9.py', wdir='C:/Users/Blair/Documents/Python/Neato XV-11 Lidar')
File "C:\Program Files (x86)\WinPython-32bit-3.4.3.3\python-3.4.3\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 682, in runfile
execfile(filename, namespace)
File "C:\Program Files (x86)\WinPython-32bit-3.4.3.3\python-3.4.3\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 85, in execfile
exec(compile(open(filename, 'rb').read(), filename, 'exec'), namespace)
File "C:/Users/Blair/Documents/Python/Neato XV-11 Lidar/Serial9.py", line 88, in <module>
print( CheckSumByte[0]) #Out of Range??
IndexError: list index out of range
肯尼:谢谢。对于两个字节来说更简单:
CheckSumByte.append(ser.read(1))
CheckSumByte.append(ser.read(1))
工作正常,但很尴尬。这些项目是字节类型。如何使用列表理解将项目添加到列表中?我想避免使用附加功能,因为它很慢。
我注意到当 CheckSumByte 的项目是整数时它不起作用。 Python 3 列表理解是否需要特殊格式才能将字节添加为字节(不转换为整数)?