WALK

The WALK Function

Function Group: Collection

WALK traverses a data structure down to a given level of depth and applies a given function to all leaf nodes. With a depth argument supplied, WALK will travel to the level of depth supplied and execute the function argument. Without the depth argument, the function argument will be applied to all leaf nodes.

Syntax

Arity: 2

WALK(arg1, arg2)

• arg1 is a function to apply to all leaf nodes within arg2
• arg2 is a collection

Arity: 3

WALK(arg1, arg2, arg3)

• arg1 is a function to apply to all leaf nodes within arg2
• arg2 is an integer representing the maximum level of depth
• arg3 is a collection

Uses

Given the following data structure:

{
  "users": {
    "user_one": {
      "first_name": "Andrey",
      "last_name": "Rudenko",
      "meta": {
        "server": "oceania",
        "activity": "high"
      }
    },
    "user_two": {
      "first_name": "Kirill",
      "last_name": "Chernyshov",
      "meta": {
        "server": "europe",
        "activity": "low"
      }
    }
  }
}

Let's say we wanted to uppercase the names of some users from the data structure above.

We could write the function WALK(UPPER, 2, users).

This would return:

{
  "users": {
    "user_one": {
      "first_name": "ANDREY",
      "last_name": "RUDENKO",
      "meta": {
        "server": "oceania",
        "activity": "high"
      }
    },
    "user_two": {
      "first_name": "KIRILL",
      "last_name": "CHERNYSHOV",
      "meta": {
        "server": "oceania",
        "activity": "low"
      }
    }
  }
}

We can also use WALK with two arguments. Given the following data structure:

{
  "users": {
    "user_one": {
      "first_name": "ANDREY",
      "last_name": "RUDENKO",
      "meta": {
        "server": "OCEANIA",
        "activity": "HIGH"
      }
    },
    "user_two": {
      "first_name": "KIRILL",
      "last_name": "CHERNYSHOV",
      "meta": {
        "server": "OCEANIA",
        "activity": "HIGH"
      }
    }
  }
}

We could lowercase all user information in the above list with WALK(LOWER, users). This would return:

{
  "users": {
    "user_one": {
      "first_name": "Andrey",
      "last_name": "Rudenko",
      "meta": {
        "server": "oceania",
        "activity": "high"
      }
    },
    "user_two": {
      "first_name": "Kirill",
      "last_name": "Chernyshov",
      "meta": {
        "server": "europe",
        "activity": "low"
      }
    }
  }
}