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I'm starting to study python, very early on. And, I tried to make a hello world, from the site of pycharm and, I came across this error, 

C:\Users\henrique.carvalho\PycharmProjects\helloworld\venv\Scripts\python.exe C:/Users/henrique.carvalho/PycharmProjects/helloworld/venv/Car.py
Traceback (most recent call last):
  File "C:/Users/henrique.carvalho/PycharmProjects/helloworld/venv/Car.py", line 1, in <module>
    class Car():
  File "C:/Users/henrique.carvalho/PycharmProjects/helloworld/venv/Car.py", line 24, in Car
    my_car = Car()
NameError: name 'Car' is not defined

How to solve?

Follow the code:

class Car:
    def __init__(self):
        self.speed = 0
        self.odometer = 0
        self.time = 0

    def say_state(self):
        print("I'm going {} kph!".format(self.speed))

    def accelerate(self):
        self.speed += 5

    def brake(self):
       self.speed -= 5

    def step(self):
        self.odometer += self.speed
        self.time += 1

    def average_speed(self):
        return self.odometer / self.time

    if __name__ == '__main__':
        my_car = Car()
        print("I'm a car!")
        while True:
            action = input("What should I do?[A]ccelerate,[B]rake, show [O]dometer, or show average [S]peed?").upper()
            if action not in "ABOS" or len(action) != 1:
                print("I don't know thow to do that")
                continue
            if action == 'A':
                my_car.accelerate()
            elif action == 'B':
                my_car.brake()
            elif action == 'O':
                print("The car has driven {} kilometers".format(my_car.odometer))
            elif action == 'S':
                print("The car's average speed was {} kph".format(my_car.average_speed()))
            my_car.step()
            my_car.say_state()

I searched here on stackoverflow but I could not figure out the answer to my case.

enter image description here

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  • 1
    indentation matters when writing code in python. It looks like you nested your main function under the class Commented Jun 26, 2018 at 17:37
  • Un-indent what you intended as your main program. At the moment, it's part of the class "Car", which prevents you from creating an object with the usual syntax. Commented Jun 26, 2018 at 17:38
  • my_car = Car() inside the definition of Car is incorrect. Why is this code inside the class definition? Commented Jun 26, 2018 at 17:39

3 Answers 3

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1

In Python, the indentation matters while writing functions, loops, and classes. Be sure to move your main function outside of the class to make sure you get the desired output.

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1 Comment

thank you! better explanation than the downvoter
0 
class Car:
  def __init__(self):
      self.speed = 0
      self.odometer = 0
      self.time = 0

  def say_state(self):
      print("I'm going {} kph!".format(self.speed))

  def accelerate(self):
      self.speed += 5

  def brake(self):
     self.speed -= 5

  def step(self):
      self.odometer += self.speed
      self.time += 1

  def average_speed(self):
      return self.odometer / self.time

if __name__ == '__main__':
  my_car = Car()
  print("I'm a car!")
  while True:
      action = input("What should I do?[A]ccelerate,[B]rake, show [O]dometer, or show average [S]peed?").upper()
      if action not in "ABOS" or len(action) != 1:
          print("I don't know thow to do that")
          continue
      if action == 'A':
          my_car.accelerate()
      elif action == 'B':
          my_car.brake()
      elif action == 'O':
         print("The car has driven {} kilometers".format(my_car.odometer))
      elif action == 'S':
          print("The car's average speed was {} kph".format(my_car.average_speed()))
      my_car.step()
      my_car.say_state()
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Comments

0

You have extra indentation from if __name__ == '__main__': line. Look at this updated code:

class Car:
    def __init__(self):
        self.speed = 0
        self.odometer = 0
        self.time = 0

    def say_state(self):
        print("I'm going {} kph!".format(self.speed))

    def accelerate(self):
        self.speed += 5

    def brake(self):
       self.speed -= 5

    def step(self):
        self.odometer += self.speed
        self.time += 1

    def average_speed(self):
        return self.odometer / self.time

if __name__ == '__main__':
    my_car = Car()
    print("I'm a car!")
    while True:
        action = input("What should I do?[A]ccelerate,[B]rake, show [O]dometer, or show average [S]peed?").upper()
        if action not in "ABOS" or len(action) != 1:
            print("I don't know thow to do that")
            continue
        if action == 'A':
            my_car.accelerate()
        elif action == 'B':
            my_car.brake()
        elif action == 'O':
            print("The car has driven {} kilometers".format(my_car.odometer))
        elif action == 'S':
            print("The car's average speed was {} kph".format(my_car.average_speed()))
        my_car.step()
        my_car.say_state()
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2 Comments

understood. thks
in ten minutes :)