Python 标准输入错误，从 pycharm 复制的代码在 CMD 中不起作用

Question

Learning python as a beginner. I wanted to copy my code into CMD but it won't work. Here is code

calculation_to_units = 24
name_of_unit = "hours"


def days_to_units(number_of_days):
    if number_of_days > 0:
      return f"{number_of_days} days are {number_of_days * calculation_to_units} {name_of_unit}"
    else:
        return "Liczba dni musi być dodatnia :)"



user_input = input("Hello user, enter amount of days you want to calculate to hours\n")
user_input_number = int(user_input)

calculated_value = days_to_units(user_input_number)
print(calculated_value)

despite the fact that it works in Pycharm. I already checked paths. I am not able to solve this problem. When I type in python3 test.py it also says C:\Users\Borys\AppData\Local\Programs\Python\Python310\python.exe: can't open file 'C:\Users\Borys\test.py': [Errno 2] No such file or directory

Also recieved this message "unable to initialize device prn in python"

My inte.net connection is so bad that it took me 10 minutes to sign up on stack overflow. Additionaly my english knowledge is too small for complex programming explainations.

Answer 1

It can be difficult to paste code that calls input() into a python shell. Both the shell and the input() function read stdin. As soon as python reads the line with input() , it calls input() and that consumes the next line on stdin. In your case, that was a python code line intended to set a variable. That line was consumbed by input and was not read or executed by python. So you got a "variable not defined" error. But you would also have gotten another error because that line was also not the stuff you wanted to input.

Suppose you had the script

val = input("Input value: ")
i_val = int(val)
print(i_val)

And pasted it into the python shell

>>> val = input("Input value: ")
Input value: i_val = int(val)
>>> print(i_val)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'i_val' is not defined. Did you mean: 'eval'?

The line i_val = int(val) was assigned to val - it was not interpreted by the shell. There would be an ">>> " if it did.