python - Python JSON 对象必须是 str,而不是“元组”
问题描述
我的代码因以下错误而崩溃:
TypeError:JSON 对象必须是 str,而不是 'tuple'
我已经打印了来自 ALPR 的通讯并收到以下信息:
(b'plate0:10 个结果\n - SBG984\t 置信度:85.7017\n - SBG98\t 置信度:83.3453\n - S8G984\t 置信度:78.3329\n - 5BG984\t 置信度:76.6761\n - S8G98\t 置信度: 75.9766\n - SDG984\t 置信度:75.5532\n - 5BG98\t 置信度:74.3198\n - SG984\t 置信度:73.3743\n - SDG98\t 置信度:73.1969\n - BG984\t 置信度:71.7671\n' , 没有任何)
我想知道如何让代码阅读并分解它?我从网上找到的另一个示例中获取了以下代码,它适用于他们,所以我不确定我做错了什么。我在下面附上了我的代码。
# Setting up Pyrebase config below
config = {
}
camera = PiCamera()
global alpr_command_args
def Take_an_Image():
global alpr_command_args
camera.start_preview()
sleep(5)
camera.capture('picture.jpg')
camera.stop_preview()
#alpr subprocess args
alpr_command = "alpr -c gb pictureold.jpg"
alpr_command_args = shlex.split(alpr_command)
read_plate()
def alpr_subprocess():
global alpr_command_args
return subprocess.Popen(alpr_command_args, stdout=subprocess.PIPE)
def alpr_json_results():
alpr_out, alpr_error = alpr_subprocess().communicate()
if not alpr_error is None:
return None, alpr_error
elif b"No license plates found." in alpr_out:
return None, None
try:
return json.loads(alpr_out), None
except (ValueError) as e:
return None, e
def read_plate():
alpr_json, alpr_error = alpr_json_results()
if not alpr_error is None:
print (alpr_error)
return
if alpr_json is None:
print ("No results!")
return
results = alpr_json["results"]
print(results)
ordinal = 0
for result in results:
candidates = result["candidates"]
for candidate in candidates:
if candidate["matches_template"] == 1:
ordinal += 1
print ("PLATE " + candidate["plate"] + candidate["confidence"])
firebase = pyrebase.initialize_app(config)
db = firebase.database()
# Setting initial values to Firebase Database on startup
data = {
"CAMERA": "OFF",
}
# Setting default values on Pi
results = db.update(data)
# This is the handler when Firebase database changes
def stream_handler(message):
path = str(message["path"]) # This is what sensor changes, e.g path returns /LED
status = str(message["data"]) # This is what the sensor says, e.g /LED says "ON"
# Getting global values
if path =="/CAMERA":
if status == "ON":
print("**TAKE PIC**")
data = {
"CAMERA": "OFF",
}
results = db.update(data)
Take_an_Image();
# Starting stream for Firebase
my_stream = db.stream(stream_handler)
更新:
通过尝试丹尼斯的方法,我收到以下错误:
线程 Thread-1 中的异常:回溯(最后一次调用):
文件“/usr/lib/python3.5/threading.py”,第 914 行,在 _bootstrap_inner self.run() 文件“/usr/lib/python3. 5/threading.py”,第 862 行,在运行 self._target(*self._args, **self._kwargs) 文件“/home/pi/.local/lib/python3.5/site-packages/pyrebase/pyrebase .py”,第 563 行,在 start_stream self.stream_handler(msg_data) 文件“camera.py”,第 96 行,在 stream_handler Take_an_Image();文件“camera.py”,第 29 行,在 Take_an_Image 中 read_plate() 文件“camera.py”,第 50 行,在 read_plate alpr_json,alpr_error = alpr_json_results() 文件“camera.py”,第 36 行,在 alpr_json_results elif “没有板成立。” 在 alpr_out:类型错误:
更新:
通过在“未找到车牌”之前添加 ab 来修复字节问题后。我现在收到以下错误:
线程 Thread-1 中的异常:回溯(最后一次调用):
文件“/usr/lib/python3.5/threading.py”,第 914 行,在 _bootstrap_inner self.run() 文件“/usr/lib/python3. 5/threading.py”,第 862 行,在运行 self._target(*self._args, **self._kwargs) 文件“/home/pi/.local/lib/python3.5/site-packages/pyrebase/pyrebase .py”,第 563 行,在 start_stream self.stream_handler(msg_data) 文件“camera.py”,第 96 行,在 stream_handler Take_an_Image();文件“camera.py”,第 29 行,在 Take_an_Image read_plate() 文件“camera.py”,第 52 行,在 read_plate alpr_json,alpr_error = alpr_json_results() 文件“camera.py”,第 46 行,在 alpr_json_results 返回 json.loads (alpr_out),无文件“/usr/lib/python3.. name )) TypeError:JSON 对象必须是 str,而不是 'bytes'
解决方案
我无法重现您获得的数据,但是尽管我尝试了您提供的输出,但我可以得出这个结论,以从您正在分析的对象中获得盘子和置信度:
import json
alpr_example = b'plate0: 10 results\n - SBG984\t confidence: 85.7017\n - SBG98\t confidence: 83.3453\n - S8G984\t confidence: 78.3329\n - 5BG984\t confidence: 76.6761\n - S8G98\t confidence: 75.9766\n - SDG984\t confidence: 75.5532\n - 5BG98\t confidence: 74.3198\n - SG984\t confidence: 73.3743\n - SDG98\t confidence: 73.1969\n - BG984\t confidence: 71.7671\n', None
def alpr_json_results():
alpr_out, alpr_error = alpr_example
if not alpr_error is None:
return None, alpr_error
elif b"No license plates found." in alpr_out:
return None, None
try:
decoded = alpr_out.decode('utf-8')
decoded = decoded.replace('-', 'plate:')
decoded = decoded[19:]
decoded = decoded.replace('plate:', ',plate:')
decoded = decoded.replace('confidence:', ',confidence:')
decoded = decoded.split(',')
decoded.pop(0)
plateList=[]
confidenceList=[]
for i, item in enumerate(decoded):
if (i%2 == 0):
print(item.replace('plate: ',''))
else:
print(item.replace('confidence: ',''))
return plateList, confidenceList
except (ValueError) as e:
return None, e
alpr_json_results()
#SBG984
#85.7017
#
#SBG98
#83.3453
#
#S8G984
#78.3329
#
#5BG984
#76.6761
#
#S8G98
#75.9766
#
#SDG984
#75.5532
#
#5BG98
#74.3198
#
#SG984
#73.3743
#
#SDG98
#73.1969
#
#BG984
#71.7671
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