Collection Methods

Collection Methods apply the following data types:

• Tuple, Map, List of Primitives, Map of Primitives, JsonArray and JsonObj
• All collection method take a lambda as argument
• (k, v) ⇒ {} for map type collections
• (i, v) ⇒ {} for list type collections.

Map

• Map()
  • return a new list populated with the results of calling a provided function on every element in the calling collection.

let arr = [1, 2, 3]
let arr2 = arr.Map((k, v) => v + 1)
printf("%v", arr2) // prints [2,3,4]

Filter

• Filter()
  • return a new list, only keeping elements that return true by the provided lambda

let arr = [1, 2, 3]
let arr2 = arr.Filter((k, v) => (v % 2 == 1))
printf("%v", arr2) // prints [1,3]

Some

• Some()
  • return true if one of the element return true

let arr = [1, 2, 3, 4, 5]
let t = arr.Some((_,e) => e == 5)
printf("%v", t) // prints true as arr contains 5
let f = arr.Some((_,e) => e == 6)
printf("%v", f) // prints false as arr does not contain 6

Find

• Find()
  • return the value element that return true by the provided lambda
  • return undefined otherwise

let arr = [
  {ID: "a", Col1: "x"},
  {ID: "b", Col1: "y"}
]
let t = arr.Find((_,e) => e.Col1 == "x")
if (t) {
  printf("Find: %v", f.ID) // prints "a"
}

Table

• Table()
  • create a table object.

let s = `
[
  {"ID": "a",  "Col1":"foo"  },
  {"ID": "b",  "Col2":"bar"  }
]`
let j = parseJson(s)
let t1 = j.Table( (_, obj) => {
  return {
    ID: obj.ID,
    Col1: obj.Col1,
    Col2: obj.Col2
  }
})

Join

• Join(delim)
  • only apply to list type collections

let arr = [1, 2, 3]
let s = arr.Join(",") // s is now the string "1,2,3"