Long entry conditions become unreadable as one expression. This shape keeps each requirement on its
own line, and it is how most trading strategy filters here are actually written.
1. The shape
# BUY — start from yes, then let each check say no
ok = True
if not (BuyVol > 0 and SellVol > 0):
ok = False
elif not (TradeAmount > TradeAmountN(1)):
ok = False
elif not (ChangePct > 0):
ok = False
elif not (Ask1 > Bid1):
ok = False
if ok:
Buy()2. What this buys you
| Property | Why it matters |
|---|
| each condition on its own line | you can comment one out and know exactly what changed |
| explicit order | the cheap checks run before the expensive ones |
| default is yes | every line can only take permission away, never grant it |
| reads as a checklist | you can still follow it a month later |
The variable name is arbitrary. What matters is the default-yes structure: written as one long
and chain the same logic is correct, and nobody can read it a month later, including you.
3. Why order is a real decision, not a style one
Conditions are evaluated in sequence, so put the ones that reject most candidates first. If
Ask1 > Bid1 rejects 2% of ticks and
ChangePct > 0 rejects 50%, running the cheap common
rejection first saves work on every tick of every symbol.
That is a performance argument, but there is a clearer one: the order of a checklist is also its
explanation. Reading top to bottom should tell someone what the strategy considers disqualifying,
in the order it considers it.
4. How this helps you test
Because each line is separable, you can run the same entry with one check removed at a time and
measure what each one contributes. That is a genuinely useful experiment and it is nearly
impossible with a single
and chain.
Watch trade count as you do it. A check that removes 90% of trades and leaves the average return
unchanged is filtering at random, and you have made your sample smaller for nothing — see
eleven conditions, four trades a month.
5. What to change first
Add a comment above each line saying what it rejects, not what it requires. "Rejects names with no
prints yet" is more useful six months later than "buy volume positive", because the rejection is
the reason the line exists.
Then check the order against your own data:
how to backtest a day trading strategy on US stocks.
Educational template for research and backtesting. Not investment advice and not a signal service.
