calling data in int() by name / dataname

blonc

data by name.

when adding data I do have the attribute name in this example well say name = SWK with in the bt.feeds.GenericCSVData()

Now with in def __init__(self): I am trying to call the data by name and can not seem to get it... IE
self.data_SWK.close does not work... self.datas_SWK.close does not work either.

referencing source data_NAME

line 109 ` - self.dataX_name -> self.datas[X].name . But this is for an analyzer, maybe its not possible any other place.

Maybe I am miss interpreting the documents.

backtrader

Yes you are misinterpreting the docs. Which means that they probably unclear. What you can reach is the name of the defined lines. A typical OHLC will have an attribute named:

self.lines.close

which can be accessed as:

self.close

In a Strategy or Analyzer you can reach the same as:

self.dataX_close

The potential benefits (which may not fit your purpose, goal)

Less typing
Save some Python lookup cycles (one dict access versus three)

Many will consider that a classical dot-based notation is clearer

self.dataX.close (and even the actual complete path self.dataX.lines.close)

blonc

@backtrader ok, that is more clear. is there any where to get an list of all datas available ? The issue that arrises for my use-case is that if you are loading in 100 data feeds into a master strategy, how to know if self.data23.close is symbol X or Y to pass it along to the sub-strategy class.

potential solution could be just as simple as passing the symbol list as a param and then running something like ["foo", "bar", "baz"].index("bar") i suppose. assume backtrader loads the data in sequential order every time from the list of symbols .

blonc

@backtrader

if not I believe I found a work around, by passing up through params the len() of data feeds added (IE how many) and then doing the following in int()

    datas_dic = {}

    for num in range(0,self.p.total_feeds):
    
        sym_name = self.datas[num]._name
        
        if not sym_name in datas_dic:
            datas_dic[sym_name] = ('self.datas%s' % num)

returns a list looking similar to :

{'WASH': 'self.datas2', 'ACN': 'self.datas1', 'SWK': 'self.datas0', 'WSBC': 'self.datas3'}

FOR CONTEXT:

this is needed because i am creating a large portfolio of pairs. I have a single master strategy that then creates sub strategies and I need to create a new sub strategy for every pair, and to create that sub strategy I need to know which datas it needs to run its calculations.