Update_at

By Goblin Docs ~ 8 min read

Update At replaces a value at a specific position in a collection.

Overview

update_at replaces a value at a specific index or key.

items | [10, 20, 30]

:update_at!(items, 1, 99)

items | [10, 20, 30]

:update_at!(items, 1, 99)

Result:

[10, 99, 30]

[10, 99, 30]

For arrays, the second argument is an index.

items | [10, 20, 30]

:update_at!(items, 2, 42)

items | [10, 20, 30]

:update_at!(items, 2, 42)

Result:

[10, 20, 42]

[10, 20, 42]

For maps, the second argument is a key.

config | {"host": "localhost", "port": "4242"}

:update_at!(config, "port", "8080")

config | {"host": "localhost", "port": "4242"}

:update_at!(config, "port", "8080")

Result:

{"host": "localhost", "port": "8080"}

{"host": "localhost", "port": "8080"}

Like most collection utilities, update_at follows Goblin's bang (!) rules.

JavaScript	Python	Java	C#	Ruby	PHP
assignment	assignment	`set()`	assignment	`[]=`	assignment
`splice()`	slice assignment	`replaceAll()`	`Replace()`	`replace`	`array_replace()`
`fill()`	list comprehension	update loop	`Select()`	`map!`	`array_map()`

The |! operator can be used to update a specific collection position.

people | ["daniel", "mike", "harry"]

people[0] |! :title(people[0])

people | ["daniel", "mike", "harry"]

people[0] |! :title(people[0])

Tip

This also works with basic update! but you'll need to see how it's done (it's slightly different). See update.

Equivalent to:

:update_at!(people, 0, :title(people[0]))

:update_at!(people, 0, :title(people[0]))

Result:

["Daniel", "mike", "harry"]

["Daniel", "mike", "harry"]

Goblin provides several targeted forms of update: