Find the number of a given symbol, and/or allow dynamic external symbol usage
symbol - any formula returning a string or a number
The current symbol number of the specified symbol, or 0 if not found
If the current symbol is MSFT, then $MSFT, Symbol, SymNum(Symbol), SymNum(?Symbol), and SymNum("MSFT") will each return the same number.
SymNum can also be used as the first argument to Extern, for cases where you need to dynamically refer to other symbols.
Extern(SymNum("MSFT"), C) is equivalent to Extern($MSFT, C), but is less efficient, because "MSFT" will be looked up every time it is processed whereas $MSFT is only looked up once, at the start of the test or scan.
A couple of possible use cases:
•Test every permutation of a pair-trade concept in a universe of 30 stocks:
•Dynamically build specific futures symbol strings: