TypeError: can't pickle Transaction objects 解决

在使用concurrent或进程池Pool进行并发操作时，遇到了这个错误

解决办法就是把map的接口修改为全局的。

from glob import glob
import os
import concurrent.futures
from multiprocessing import Pool
import lmdb
import time

class VerifyLabel:
	def __init__(self):
		self.file_name = ''
		...
	def check_txt(self, file_name):
		print(f'file_name:{self.file_name}')

if __name__ == "__main__":
    verify = VerifyLabel()

    with concurrent.futures.ProcessPoolExecutor() as executor:
        roots = glob('/root/images/*.jpg')
    
        executor.map(verify.get_text, roots)

像上面的代码在运行时，就会报这个can’t pickle Transaction objects 错误。

map不能直接操作对象

改为：

from glob import glob
import os
import concurrent.futures
from multiprocessing import Pool
import lmdb
import time

A = None

class VerifyLabel:
	def __init__(self):
		self.file_name = ''
	def check_txt(self, file_name):
		print(f'file_name:{self.file_name}')

def check_txt( file_name):
		global A
		print(f'file_name:{A.file_name}')
		
if __name__ == "__main__":
    verify = VerifyLabel()
	A = verify
	
    with concurrent.futures.ProcessPoolExecutor() as executor:
        roots = glob('/root/images/*.jpg')
    
        executor.map(verify.get_text, roots)

这样就不会错了。