Search a list of Dictionaries

Question

Hello, 
 
 Is there a way in appian where I can search a list of dictionaries for any item in that list that meets a specific set of properties 
 
 For example, say I have the following list: 
 {{storeNum: "003", taskCode: "A", numOfTasks: 1292}, 
 {storeNum: "003", taskCode: "B", numOfTasks: 5}, 
 {storeNum: "003", taskCode: "C", numOfTasks: 8}, 
 {storeNum: "003", taskCode: "D", numOfTasks: 5}, 
 {storeNum: "004", taskCode: "A", numOfTasks: 208}, 
 {storeNum: "004", taskCode: "C", numOfTasks: 2}} 
 Now, I want a function, that when I feed it a storeNum and taskCode, to return to me the numOfTasks if it exists in the list, and returns 0 (or any indication) when no dictionary items with the specified combination of storeNum and taskCode exists in the list. 
 
 for example, if I call function(storeNum: "003", taskCode:"A") it will return 1292 
 However, if I call function(storeNum: "004", taskCode:"B") it will return 0 
 
 Is there something like this, or similar? I am struggling to wrap my head around how list comprehension works in appian. 
 thank you,

Siddharth · Answer

You can achieve this in Appian by creating an expression rule. Your rule will have inputs as the storeNum and taskCode. 
 Please go through the below links which will help you out - 
 https://docs.appian.com/suite/help/21.3/Expression_Rules.html 
 https://docs.appian.com/suite/help/21.3/Appian_Functions.html 
 A sample format would be something like this. 
 
 a!localVariables(
 local!data: {
 a!map(
 storeNum: "003",
 taskCode: "A",
 numOfTasks: 1292
 ),
 a!map(
 storeNum: "003",
 taskCode: "B",
 numOfTasks: 5
 ),
 a!map(
 storeNum: "003",
 taskCode: "C",
 numOfTasks: 8
 ),
 a!map(
 storeNum: "004",
 taskCode: "A",
 numOfTasks: 208
 ),
 a!map(
 storeNum: "004",
 taskCode: "C",
 numOfTasks: 2
 )
 },
 local!indexToQuery: intersection(
 wherecontains(ri!storeNum, local!data.storeNum),
 wherecontains(ri!taskCode, local!data.taskCode)
 ),
 if(
 count(local!indexToQuery) = 0,
 0,
 index(
 local!data.numOfTasks,
 local!indexToQuery
 )
 )
)