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 from the table (parameter applicable only if the target variable is a table).	None	String&String
Global		If the variable is 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]

 

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