This topic describes the syntax and parameters of list functions. This topic also provides examples on how to use the functions.

Functions

Function Description
lst_make Creates a list.
lst_insert Inserts elements to a specified position in a list.
lst_append Appends elements to a list.
lst_delete_at Deletes the element at a specified position from a list.
lst_reverse Reverses the order of elements in a list.
op_slice Returns specific elements.
lst_get Returns the element at a specified position in a list or a tuple.
op_len Calculates the number of elements in a list or a tuple.

lst_make

The lst_make function creates a list.
  • Syntax

    lst_make(value1, value2, ...)
  • Parameters

    Parameter Type Required Description
    value1 String Yes The element of the list.
    value2 String Yes The element of the list.
  • Response

    The created list is returned.

  • Examples

    • Raw log
      content:test
    • Transformation rule
      e_set("hello", lst_make("k1","k2"))
    • Result
      content:test
      hello:["k1", "k2"]

lst_insert

The lst_insert function inserts elements to a specified position in a list.
  • Syntax

    lst_insert(list_string, location, value1, value2, ...)
  • Parameters

    Parameter Type Required Description
    list_string List Yes The input list.
    location Number Yes The position to which you want to insert elements.
    value1 String Yes The element that you want to insert.
    value2 String No The element that you want to insert.
  • Response

    The list to which the elements are inserted is returned.

  • Examples

    • Raw log
      ctx: ["k1","k2"]
    • Transformation rule
      e_set("hello", lst_insert(v("ctx"), 0, "k0"))
    • Result
      ctx: ["k1","k2"]
      hello: ["k0", "k1", "k2"]

lst_append

The lst_append function appends elements to a list.
  • Syntax

    lst_append(list_string, value1, value2, ...)
  • Parameters

    Parameter Type Required Description
    list_string List Yes The input list.
    value1 String Yes The element that you want to append.
    value2 String No The element that you want to append.
  • Response

    The list to which the elements are appended is returned.

  • Examples

    • Raw log
      ctx: ["k1","k2"]
    • Transformation rule
      e_set("hello", lst_append(v("ctx"), "k3"))
    • Result
      ctx: ["k1","k2"]
      hello: ["k1", "k2", "k3"]

lst_delete_at

The lst_delete_at function deletes the element at a specified position from a list.
  • Syntax

    lst_delete_at(list_string, location)
  • Parameters

    Parameter Type Required Description
    list_string list Yes The input list.
    location Number Yes The position of the element that you want to delete. The position of the first element is 0.
  • Response

    The list from which the element is deleted is returned.

  • Examples

    • Raw log
      ctx: ["k1","k2"]
    • Transformation rule
      e_set("hello", lst_delete_at(v("ctx"),1))
    • Result
      ctx: ["k1","k2"]
      hello: ["k1"]

lst_reverse

The lst_reverse function reverses the order of elements in a list.
  • Syntax

    lst_reverse(list_string)
  • Parameters

    Parameter Type Required Description
    list_string List Yes The input list.
  • Response

    The list whose order of elements is reversed is returned.

  • Examples

    • Raw log
      ctx: ["v1","v2"]
    • Transformation rule
      e_set("hello", lst_reverse(v("ctx")))
    • Result
      ctx: ["v1","v2"]
      hello: ["v2","v1"]

lst_get

The lst_get function returns the element at a specified position in a list or a tuple.
  • Syntax

    lst_get(list_string, location)
  • Parameters

    Parameter Type Required Description
    list_string List Yes The input list.
    location Int Yes The position of the element that you want to obtain. The position of the first element is 0. For example, if the input list is ["a","b","c"], you can obtain the elements at the following positions: 0, 1, and 2.
  • Response

    The element at the specified position is returned.

  • Examples

    • Raw log
      ctx: ["v1","v2"]
    • Transformation rule
      e_set("hello", lst_get(v("ctx"),1))
    • Result
      ctx: ["v1","v2"]
      hello: "v2"