Python concatenation of string

Question

I'm doing python programming and this is class unit of that. and the code is not printing the right answer.

class Car(object):
    condition = "new"
    def __init__(self, model, color, mpg):
        self.model = model
        self.color = color
        self.mpg   = mpg
    def display_car(self):
        print "This is a "+ self.color + self.model+ " with "+str(self.mpg)+"MPG"

my_car = Car("DeLorean", "silver", 88)
print my_car.display_car()

I'm trying to print This is a silver DeLorean with 88 MPG.

Answer 1

Try this version of display_car method instead:

def display_car(self):
    print "This is a %s %s with %d MPG." % (self.color, self.model, self.mpg)

Or, you can make use of format:

def display_car(self):
    print "This is a {0} {1} with {2} MPG.".format(self.color, self.model, self.mpg)

Both versions print This is a silver DeLorean with 88 MPG.

I think you see that both versions are more readable than your's with string concatenation.

You can make it even more readable by using format with named arguments:

def display_car(self):
    print "This is a {color} {model} with {mpg} MPG.".format(color=self.color, model=self.model, mpg=self.mpg)

Also, you have None printed too - replace print my_car.display_car() with my_car.display_car().