Python “instancemethod”对象没有带有类变量的属性“__getitem__”
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'instancemethod' object has no attribute '__getitem__' with class variables
提问by SquarePie
I'm trying to create a python class to control stepper motors using my Raspberry Pi. It mostly works, however I keep on getting an "'instancemethod' object has no attribute '__getitem__'error whenever I define a list as a class variable. The error message lists this piece of code as the culprit but I can't see anything wrong with it if seq[self.StepCounter][pin]!=0:. It will work if I define it as an instance variable or a global variable though.
This is my code:
import RPi.GPIO as GPIO
import time
debug = True
我正在尝试创建一个 python 类来使用我的 Raspberry Pi 控制步进电机。它主要有效，但是'__getitem__'每当我将列表定义为类变量时，我都会不断收到“'instancemethod'对象没有属性错误。错误消息将这段代码列为罪魁祸首，但我看不出有什么问题if seq[self.StepCounter][pin]!=0:。如果我将其定义为实例变量或全局变量，它将起作用。这是我的代码：import RPi.GPIO as GPIO import time debug = True
class stepper:
clockwise = []
clockwise = range(0,4)
clockwise[0] = [1,0,0,0]
clockwise[1] = [0,1,0,0]
clockwise[2] = [0,0,1,0]
clockwise[3] = [0,0,0,1]
def __init__(self,pin1,pin2,pin3,pin4):
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
self.pin1 = pin1
self.pin2 = pin2
self.pin3 = pin3
self.pin4 = pin4
self.StepCounter = 0
self.pinarray = [pin1,pin2,pin3,pin4]
for pin in self.pinarray:
if debug == True:
print "Setup pin " + str(pin)
GPIO.setup(pin,GPIO.OUT)
GPIO.output(pin, False)
self.stepNum = 512.0
self.coilNum = 4.0
def setup(self,stepNum,coilNum):
self.stepNum = float(stepNum)
self.coilNum = float(coilNum)
self.partNum = self.coilNum * self.stepNum
def clockwise(self,speed):
seq = stepper.clockwise
self.WaitTime = (1.0 / (self.stepNum * self.coilNum)) * speed
for pin in range(0, 4):
xpin = self.pinarray[pin]
if seq[self.StepCounter][pin]!=0:
GPIO.output(xpin, True)
else:
GPIO.output(xpin, False)
self.StepCounter += 1
if (self.StepCounter==len(seq)):
self.StepCounter = 0
if (self.StepCounter<0):
self.StepCounter = len(seq)
time.sleep(self.WaitTime)
print "Adding Motor Instance"
motor = stepper(24,25,8,7)
print "Spinning Motor"
while "True":
motor.clockwise(5)
Please could someone tell me what's wrong with it and explain why. Thanks
请有人告诉我它有什么问题并解释原因。谢谢
采纳答案by DSM
You didn't post the full traceback, but I can take a guess:
您没有发布完整的回溯，但我可以猜测：
def clockwise(self,speed):
seq = stepper.clockwise
self.WaitTime = (1.0 / (self.stepNum * self.coilNum)) * speed
for pin in range(0, 4):
xpin = self.pinarray[pin]
if seq[self.StepCounter][pin]!=0:
You set seqequal to the method stepper.clockwiseon the first line. Then a few lines later you try to index into it: seq[self.StepCounter]. But what does it mean to get the self.StepCounter-th element of a method?
您设置为seq等于stepper.clockwise第一行的方法。然后几行之后，您尝试对其进行索引：seq[self.StepCounter]. 但是获取方法的self.StepCounter第 -th 个元素是什么意思？
Nothing, because:
没什么，因为：
'instancemethod' object has no attribute '__getitem__'
You shouldn't use clockwiseboth as the name of a list and as the name of a method; only the last-executed definition will hold, so by the time you get to seq = stepper.clockwise, it's the method, not the list.
你不应该同时使用clockwise列表的名称和方法的名称；只有最后执行的定义会成立，所以当你到达时seq = stepper.clockwise，它是方法，而不是列表。
