PySerial [Error 5] Access is Denied

Question

I am trying to write a program in Python that will loop to keep checking the serial port (COM4) and print out a message when the character \"1\" is read from the serial port

Answer 1

Please, take care with the python versions.

From the pyserial manual about: class serial.Serial https://pyserial.readthedocs.io/en/latest/pyserial_api.html#classes

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The port is immediately opened on object creation, when a port is given. It is not opened when port is None and a successive call to open() is required.

port is a device name: depending on operating system. e.g. /dev/ttyUSB0 on GNU/Linux or COM3 on Windows.

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Changed in version 3.0: numbers as port argument are no longer supported