title: How to default IntegerField in Django
body: <p>I was studying some Django, and came across a small problem.</p>
  
  <p>I am looking for a way to make suit_length equal to customer's height by default. This kind of code works for me:</p>
  
  <pre><code>    class Customer(models.Model):
          name = models.CharField(max_length=20)
          height = models.IntegerField(default=170)
  
      class Suit(models.Model)
          customer = models.ForeignKey(Customer)
          suit_design = models.CharField(max_length=100)
          suit_length = models.IntegerField(default=0)
          def get_height(self):
              self.suit_length = self.customer.height
              return
  </code></pre>
  
  <p>But every time I create a new Suit its default suit_length = 0, and I have to run get_height() to get what I want. Is there a way to default suit_length to customer.height and to avoid running get_height() every time I create a new Suit? I am probably looking for smth like this:</p>
  
  <pre><code>    class Customer(models.Model):
          name = models.CharField(max_length=20)
          height = models.IntegerField(default=170)
  
      class Suit(models.Model)
          customer = models.ForeignKey(Customer)
          suit_design = models.CharField(max_length=500)
          suit_length = models.IntegerField(default=lambda:self.customer.height)
  </code></pre>
  
  <p>But this code doesn't work.</p>