从命令行运行 python 脚本时未找到模块错误

Question

I have a python script which accepts the file.txt as an argument.

When I run from the windows command line, it complains about the following error.

*C:\Projects\ATR220TA\ISO8583_Payment>python C:\Projects\ATR220TA\ISO8583_Payment\ISO8583.py C:\Projects\ISO8583.txt
Traceback (most recent call last):
  File "C:\Projects\ATR220TA\ISO8583_Payment\ISO8583.py", line 19, in <module>
    from ISO8583_Payment.ISOErrors import InvalidIso8583, ValueToLarge, InvalidValueType, InvalidBitType, BitInexistent, \
ModuleNotFoundError: No module named 'ISO8583_Payment'
C:\Projects\ATR220TA\ISO8583_Payment>pause*

Basically, ISO8583_Payment is a subfolder of my main project, but for some reason, ISO8583_Payment is assumed as a module and throws the "module not found" an error.

ISO8583.py

def ParseRawMessage(ISO8583TextFile):
    with open(ISO8583TextFile, 'rb') as in_file:
        contents = in_file.read()
        hex_bytes = binascii.hexlify(contents)
        IsoStr = hex_bytes.decode("ascii")
        Iso8583 = ISO8583()
        try:
            Iso8583.setIsoContent(IsoStr)
        except InvalidMTI as error:
            print("{0}".format(error))
        except InvalidBitType as error:
            print("{0}".format(error))
        except ValueToLarge as error:
            print("{0}".format(error))
        except InvalidValueType as error:
            print("{0}".format(error))
        except BitInexistent as error:
            print("{0}".format(error))
        except BitNotSet as error:
            print("{0}".format(error))
        except InvalidIso8583 as error:
            print("{0}".format(error))
        bitsAndValuesDictionary = Iso8583.getBitsAndValues()
        for v in bitsAndValuesDictionary:
            print('%s (BIT-%s) = %s' % (v['name'], v['bit'], v['value']))


if __name__ == '__main__':
    ParseRawMessage(sys.argv[1])

Answer 1

When you write

from ISO8583_Payment.ISOErrors import InvalidIso8583, ValueToLarge, \
InvalidValueType, InvalidBitType, BitInexistent

You are telling Python that ISO8583_Payment is a module.

So, you can add an empty __init__.py file to that subdirectory or, if you want to leave it as a directory, use this code to add it to the system path so it will be searched:

import sys
sys.path.append("/ISO8583_Payment")

Answer 2

@Mikah Barnett, Your suggestion did not work when I run from the command prompt. I have previously mentioned that it worked for me but, I just realized it only works when I run from the pyCharm IDE (sorry for the confusion). Both ISO8583.py and ISO8583Errors.py are located inside the ISO8583_payment folder. Also, I created __init.py__ inside ISO8583_Payment folder as per your suggestion.

ISO8583.py

import sys
sys.path.append("/ISO8583_Payment")
from ISO8583_Payment.ISOErrors import InvalidBitType,InvalidMTI,InvalidValueType,InvalidIso8583,ValueToLarge,BitInexistent,BitNotSet
''' I did not copy all the source code in here ''''

def ParseRawMessage(ISO8583TextFile):
    with open(ISO8583TextFile, 'rb') as in_file:
        contents = in_file.read()
        hex_bytes = binascii.hexlify(contents)
        IsoStr = hex_bytes.decode("ascii")
        Iso8583 = ISO8583()
        try:
            Iso8583.setIsoContent(IsoStr)
        except InvalidMTI as error:
            print("{0}".format(error))
        except InvalidBitType as error:
            print("{0}".format(error))
        except ValueToLarge as error:
            print("{0}".format(error))
        except InvalidValueType as error:
            print("{0}".format(error))
        except BitInexistent as error:
            print("{0}".format(error))
        except BitNotSet as error:
            print("{0}".format(error))
        except InvalidIso8583 as error:
            print("{0}".format(error))
        bitsAndValuesDictionary = Iso8583.getBitsAndValues()
        for v in bitsAndValuesDictionary:
            print('%s (BIT-%s) = %s' % (v['name'], v['bit'], v['value']))


if __name__ == '__main__':
    ParseRawMessage(sys.argv[1])

ISOErrors.py

class ValueToLarge(Exception):

    def __init__(self, value):
        self.str = value
    def __str__(self):
        return repr(self.str)

class BitInexistent(Exception):

    def __init__(self, value):
        self.str = value
    def __str__(self):
        return repr(self.str)       


class InvalidValueType(Exception):

    def __init__(self, value):
        self.str = value
    def __str__(self):
        return repr(self.str)       


class InvalidBitType(Exception):

    def __init__(self, value):
        self.str = value
    def __str__(self):
        return repr(self.str)       


class InvalidIso8583(Exception):

    def __init__(self, value):
        self.str = value
    def __str__(self):
        return repr(self.str)           


class InvalidMTI(Exception):

    def __init__(self, value):
        self.str = value
    def __str__(self):
        return repr(self.str)       

#Exception that indicate that bit is not there.
class BitNotSet(Exception):

    def __init__(self, value):
        self.str = value
    def __str__(self):
        return repr(

When I run form the command prompt, I still get following error.

C:\Projects\ATR220TA_Work_On_Progress\ISO8583_Payment>python C:\Projects\ATR220TA_Work_On_Progress\ISO8583_Payment
C:\Users\gobiraaj.anandavel\AppData\Local\Programs\Python\Python37-32\python.exe: can't find '__main__' module in 'C:\\Projects\\ATR220TA_Work_On_Progress\\ISO8583_Payment'