What is causing this "TypeError: a bytes-like object is required, not 'str'" error?

Question

我知道这可能是个小问题，但我真的找不到解决这个问题的方法。我正在使用此代码：

# Import the modules
from __future__ import division
import spidev, datetime, time
from sys import exit
import RPi.GPIO as GPIO

# Setup SPI
spi = spidev.SpiDev()
spi.open(0, 0)
spi.mode = 3

# Constants
accres = 16
accrate = 15

# Set GPIO chip select pins
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
cs1 = 23
cs2 = 24
motor = 18
GPIO.setup(cs1, GPIO.OUT)
GPIO.setup(cs2, GPIO.OUT)
GPIO.setup(motor, GPIO.OUT)

# Note: the duty cycle goes from 0.0 to 100.0, with 100.0 being no motor movement,
# and 0.0 being the maximum motor speed.
motor_output = GPIO.PWM(motor, 60)

# Initialize the ADXL345
def initadxl345():
    # Set data rate (accrate=15 -> 3200 Hz, 14=1600 Hz, 13=800 Hz, 12=400 Hz, 11=200 Hz, 10=100 Hz etc.)
    spi.xfer2([44, accrate])

    # Enable full range (10 bits resolution) and +/- 16g 4 LSB
    spi.xfer2([49, accres])

# Read the first ADXL x-y-z axes
def readadxl345_1():
    # Chip select pin ensures that the first sensor is being read by grounding its pin
    GPIO.output(cs1, 0)
    GPIO.output(cs2 ,1)

    rx = spi.xfer2([242, 0, 0, 0, 0, 0, 0])
    out = [rx[1] | (rx[2] << 8), rx[3] | (rx[4] << 8), rx[5] | (rx[6] << 8)]
    # Format x-axis
    if (out[0] & (1 << 16 - 1 )):
        out[0] = out[0] - (1 << 16)
    # Format y-axis
    if (out[1] & (1 << 16 - 1 )):
        out[1] = out[1] - (1<<16)
    # Format z-axis
    if (out[2] & (1 << 16 - 1 )):
        out[2] = out[2] - (1 << 16)
    # Return human readable values
    return out

# Read the second ADXL x-y-z axes
def readadxl345_2():
    # Chip select pin ensures that the first sensor is being read by grounding its pin
    GPIO.output(cs1, 1)
    GPIO.output(cs2 ,0)

    rx = spi.xfer2([242, 0, 0, 0, 0, 0, 0])
    out = [rx[1] | (rx[2] << 8), rx[3] | (rx[4] << 8), rx[5] | (rx[6] << 8)]
    # Format x-axis
    if (out[0] & (1 << 16 - 1 )):
        out[0] = out[0] - (1 << 16)
    # Format y-axis
    if (out[1] & (1 << 16 - 1 )):
        out[1] = out[1] - (1<<16)
    # Format z-axis
    if (out[2] & (1 << 16 - 1 )):
        out[2] = out[2] - (1 << 16)
    # Return human readable values
    return out

print("Vibration Reader Initializing...")
time.sleep(1)
print(GPIO.RPI_INFO)

response = input("Proceed measurements? [Y, n]")
pwm_speed = float(input("Motor PWM value: "))

if response == "Y" or "y":
    # Initialize the ADXL345 accelerometer
    print("Initializing ADXL345s...")
    initadxl345()
    motor_output.start(pwm_speed)

    timeout = 0.0003125 / 2 # timeout=1/samplerate=>not sufficient measurements. Half the time is sufficient (don't know why!)

    timetosend = 1

    while(1):
       with open('/proc/uptime', 'r') as f: # get uptime
           uptime_start = float(f.readline().split()[0])
       uptime_last = uptime_start
       active_file_first = "10bit" + str(accres) + 'g' + '.csv'
       file = open('/var/log/sensor/' + active_file_first, 'wb')
       while uptime_last < uptime_start + timetosend:

           time1 = str(datetime.datetime.now().strftime('%S.%f'))
           sensor1 = readadxl345_1()
           sensor2 = readadxl345_2()
           file.write(str(sensor1[0]) + ',' + str(sensor1[1]) + ',' + str(sensor1[2]) + ',' + str(sensor2[0]) + ',' + str(sensor2[1]) + ',' + str(sensor2[2]) + ',' + time1 + '\n')

           # Print data every "timeout" second
           elapsed = time.clock()
           current = 0
           while(current < timeout):
               current = time.clock() - elapsed

    motor_output.stop
    print("Motor shutting off and cleaning up GPIO.")
    GPIO.cleanup()

elif response == "N" or "n":
    print("Quitting...")
    time.sleep(1)
    quit()

解释器给出了第 106 行的问题，说

Traceback (most recent call last):
  File "accelerometer.py", line 106, in <module>
    file.write(str(sensor1[0]) + ',' + str(sensor1[1]) + ',' + str(sensor1[2]) + ',' + str(sensor2[0]) + ',' + str(sensor2[1]) + ',' + str(sensor2[2]) + ',' + time1 + '\n')
TypeError: a bytes-like object is required, not 'str'

有人知道如何解决这个问题或 improve/streamline 代码吗？我正在使用 Python 3.8.1，我正在 Linux 机器上进行。

Answer 1

您已在 "wb" 模式下打开文件进行写入。

file = open('/var/log/sensor/' + active_file_first, 'wb')

所以希望写入文件的数据是 byte 个对象。

您需要将正在写入的字符串转换为 byte 对象，或者可能将打开文件的模式更改为 "w" 模式。

file = open('/var/log/sensor/' + active_file_first, 'w')

What is causing this "TypeError: a bytes-like object is required, not 'str'" error?

What is causing this "TypeError: a bytes-like object is required, not 'str'" error?

python

typeerror

raspberry-pi3