How to Check If A Symbol Exists in Amibroker DB

[amitabhanandy]

Hi,

I am working on an AFL where I determine the name of a Ticker based on some dynamic parameters.

Say Sym_Z = X + Y ; where both X and Y are some dynamic strings. While care is taken that both X and Y are valid values, sometimes I am encountering issue where the ticker formed combining X and Y is not a ticker present in Amibroker DB and thereby in downstrem foreign calls its causing issues. So I need to ensure that Sym_Z is a valid ticker before initiating computation on that ticker.

I tried using Foreign call and validating the outcome. But no luck yet. Can someone please guide me on how can I come to a binary conclusion that Sym_Z exists in Amibroker DB ? I am not sure to what should I compare the outcome {EMPTY} to determine its an invalid symbol. If any other cleaner method is available, please suggest.

My trace attempt on below code chuck and its outcome is as below.

_TRACE("!CLEAR!");
Sym_Z_Exists = Foreign(Sym_Z,"C");
_TRACE("Sym_Z_Exists =>" + Sym_Z_Exists);

Thanks,
Nandy

[Tomasz]

{EMPTY} is just other name for Null value and that is precisely how you would check for existence:

fc = Foreign("NONEXISTING","C");

if( typeof( fc ) == "number" AND IsNull( fc ) )
{
  printf("Symbol does NOT exist\n");
}

Or alternative code:

fc = Foreign("NONEXISTING","C");

if( IsNull( fc[BarCount-1] ) )
{
  printf("Symbol does NOT exist\n");
}

[amitabhanandy]

Dear Tomasz,

Thank you for your quick help. Really appreciate it.

Thanks,
Nandy