Builder pattern equivalent in Python

Question

In Java, you can use the builder pattern to provide a more readable means to instantiating a class with many parameters. In the builder pattern, one constructs a configurati

Answer 1

I disagree with @MechanicalSnail. I think a builder implementation similar to one referenced by the poster is still very useful in some cases. Named parameters will only allow you to simply set member variables. If you want to do something slightly more complicated, you're out of luck. In my example I use the classic builder pattern to create an array.

class Row_Builder(object):
  def __init__(self):
    self.row = ['' for i in range(170)]

  def with_fy(self, fiscal_year):
    self.row[FISCAL_YEAR] = fiscal_year
    return self

  def with_id(self, batch_id):
    self.row[BATCH_ID] = batch_id
    return self

  def build(self):
    return self.row

Using it:

row_FY13_888 = Row_Builder().with_fy('FY13').with_id('888').build()