How to access the "params" tuple?

niklay

Hi there,
I started with the Quickstart tutorials and found some confusing code (see attached). The "params" tuple is created with two separate tuples inside. However, I can access these inside tuples by typing params.maperiod . However, if I rename params to another name I cannot access them anymore.

 class TestStrategy():
  params = (
      ('maperiod', 15),
      ('printlog', False),
  )

def log(self, txt, dt=None, doprint=False):
    if self.params.printlog or doprint:
        dt = dt or self.datas[0].datetime.date(0)
        print('%s, %s' % (dt.isoformat(), txt))

Laurent Michelizza

I don't think you should rename the variable params as it is part of the default strategy that you are inheriting. You can also access it simply with .p like below:

self.p.printlog

backtrader

@niklay said in How to access the "params" tuple?:

I started with the Quickstart tutorials and found some confusing code (see attached). The "params" tuple is created with two separate tuples inside. However, I can access these inside tuples by typing params.maperiod .

What's exactly the confusing part? You declare params (which you can also declare as a dict) and you can access them. It's a declarative style. As pointed out by @Laurent-Michelizza , there is a shorhand notation where params is shortened to p

@niklay said in How to access the "params" tuple?:

However, if I rename params to another name I cannot access them anymore.

Of course. How are you expecting the platform to know which params have been defined if you give the declaration a different name?