Wie extrahiere ich ein Tupel, das ein Element aus der Tupel-Liste enthält?

Question

Ich habe diese Liste von Tupeln:

[{denomination_flexible_denomination,236,9,2,"1","CORE BALANCE",0,10,"1","500","100","100",null,"ecrlrlep_facilito","ecrlrlep_facilito","true","[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10220\"}, {tipo_trx_consulta, \"310220\"}, {payment_type, \"electronic_money\"}]"}, 
{denomination_flexible_denomination,239,8,2,"2","CORE BALANCE",0,10,"1","500","100","100",null,"ecrlrlep_facilito","ecrlrlep_facilito","true","[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"}] 

und ich brauche das Tupel zu extrahieren, die denomination_flexible_denomination enthält 239. jemand tut wissen, wie das zu tun?

Answer 1

Verwenden Sie lists:keyfind/3. Ihre Argumente sind der Schlüssel (in diesem Fall 239), die Position in dem Tupel (2, wie es der zweite Tupelelement ist), und die Tupel-Liste:

> lists:keyfind(239, 2, TupleList). 
{denomination_flexible_denomination,239,8,2,"2", 
            "CORE BALANCE",0,10,"1","500","100","100",null, 
            "ecrlrlep_facilito","ecrlrlep_facilito","true", 
            "[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"} 

Wenn kein Anpassungselement ist, lists:keyfind/3 kehrt false.

Answer 2

Der einfachste Weg lists:filter

TupleList = [{denomination_flexible_denomination,236,9,2,"1","CORE BALANCE",0,10,"1","500","100","100",null,"ecrlrlep_facilito","ecrlrlep_facilito","true","[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10220\"}, {tipo_trx_consulta, \"310220\"}, {payment_type, \"electronic_money\"}]"},{denomination_flexible_denomination,239,8,2,"2","CORE BALANCE",0,10,"1","500","100","100",null,"ecrlrlep_facilito","ecrlrlep_facilito","true","[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"}]. 

R=lists:filter(fun(Tuple)->(element(1,Tuple)=:=denomination_flexible_denomination) and (element(2,Tuple)=:=239) end,TupleList). 

Answer 3

1> L = [{denomination_flexible_denomination,236,9,2,"1","CORE BALANCE",0,10,"1","500","100","100",null,"ecrlrlep_facilito","ecrlrlep_facilito","true","[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10220\"}, {tipo_trx_consulta, \"310220\"}, {payment_type, \"electronic_money\"}]"}, 
1> {denomination_flexible_denomination,239,8,2,"2","CORE BALANCE",0,10,"1","500","100","100",null,"ecrlrlep_facilito","ecrlrlep_facilito","true","[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"}]. 
[{denomination_flexible_denomination,236,9,2,"1", 
            "CORE BALANCE",0,10,"1","500","100","100",null, 
            "ecrlrlep_facilito","ecrlrlep_facilito","true", 
            "[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10220\"}, {tipo_trx_consulta, \"310220\"}, {payment_type, \"electronic_money\"}]"}, 
{denomination_flexible_denomination,239,8,2,"2", 
            "CORE BALANCE",0,10,"1","500","100","100",null, 
            "ecrlrlep_facilito","ecrlrlep_facilito","true", 
            "[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"}] 
2> [ X || {denomination_flexible_denomination, 239, _,_,_,_,_,_,_,_,_,_,_,_,_,_,_} =X <- L].    
[{denomination_flexible_denomination,239,8,2,"2", 
            "CORE BALANCE",0,10,"1","500","100","100",null, 
            "ecrlrlep_facilito","ecrlrlep_facilito","true", 
            "[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"}] 

oder

3> [ X || X <- L, element(1,X) =:= denomination_flexible_denomination, element(2, X) =:= 239]. 
[{denomination_flexible_denomination,239,8,2,"2", 
            "CORE BALANCE",0,10,"1","500","100","100",null, 
            "ecrlrlep_facilito","ecrlrlep_facilito","true", 
            "[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"}] 

oder

4> list_to_tuple([ list_to_atom("field_" ++ integer_to_list(X)) || X <- lists:seq(1,16) ]). 
{field_1,field_2,field_3,field_4,field_5,field_6,field_7, 
     field_8,field_9,field_10,field_11,field_12,field_13, 
     field_14,field_15,field_16} 
5> rd(denomination_flexible_denomination, v(-1)).            
denomination_flexible_denomination 
6> [ X || #denomination_flexible_denomination{field_1 = 239} = X <- L]. 
[#denomination_flexible_denomination{field_1 = 239, 
            field_2 = 8,field_3 = 2,field_4 = "2", 
            field_5 = "CORE BALANCE",field_6 = 0,field_7 = 10, 
            field_8 = "1",field_9 = "500",field_10 = "100", 
            field_11 = "100",field_12 = null, 
            field_13 = "ecrlrlep_facilito", 
            field_14 = "ecrlrlep_facilito",field_15 = "true", 
            field_16 = "[{codigo_producto, \"0010701020\"}, {tipo_trx_pago, \"10120\"}, {tipo_trx_consulta, \"310120\"}, {payment_type, \"electronic_money\"}]"}] 

zu verwenden