DropFront

Name	-	Description	Default	Type
<input>		Any input is ignored.		Any
<output>		The input to this shard is passed through as its output.		Any
Name		The name of the variable.	""	String&Any
Key		The key of the value to read/write from/in the table (parameter applicable only if the target variable is or will become a table).	None	String&String
Global		If the variable is or should be available to all of the wires in the same mesh.	false	Bool

Drops the first element of the sequence variable passed in the :Name parameter. Works only on sequences.

Details

DropFront drops (removes) the first element of the sequence variable that has been passed to in the :Name parameter.

This shard works on both sequences and tables. Parameter :Key applies only to tables.

Since variables may be locally scoped (created with (:Global false); exists only for current wire) or globally scoped (created with (:Global true); exists for all wires of that mesh), both parameters :Global and :Name are used in combination to identify the correct variable to drop elements from.

Any input to this shard is ignored and instead passed through as its output.

See also

• Clear
• Drop
• Erase
• Pop
• PopFront
• PrependTo
• Remove

Examples

CodeOutput

;; drop first element from a local sequence
[10 20 30 40] >= .seq           ;; create a local sequence
(Get .seq) (Log)                ;; local sequence => [10, 20, 30, 40]
(DropFront :Name .seq)          ;; drops the first element i.e., 10
(Get .seq) (Log)                ;; updated sequence => [20 30 40]

;; drop first element from a same-name global sequence
[11 21 31 41] >== .seq          ;; create a same-name global sequence
(Get .seq :Global true) (Log)   ;; local sequence => [11, 21, 31, 41]
(DropFront .seq :Global true)   ;; drops the first element i.e., 11
(Get .seq :Global true) (Log)   ;; updated sequence => [21, 31, 41]

[info] Set - Warning: setting an already exposed variable "seq", use Update to avoid this warning.
[info] [shards/General/DropFront/DropFront.edn] [10, 20, 30, 40]
[info] [shards/General/DropFront/DropFront.edn] [20, 30, 40]
[info] [shards/General/DropFront/DropFront.edn] [11, 21, 31, 41]
[info] [shards/General/DropFront/DropFront.edn] [21, 31, 41]

 

---