List Processing (Part 5) – Item Extraction

These functions allow you to extract one or more items from an array.

ARRAY_INDEX

Definition: ARRAY_INDEX(Array $list, Number $index)

Get the element at index $i. Indexes range from 1 (the first element) to ARRAY_LENGTH($list).

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Examples

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Index Result
ARRAY_INDEX($list, 1) Z
ARRAY_INDEX($list, 2) Y
ARRAY_INDEX($list, 3) X
ARRAY_INDEX($list, 4) W

ARRAY_FIRST

Definition: ARRAY_FIRST(Array $list)

Equivalent to ARRAY_INDEX($list, 1)

In this example:

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ARRAY_FIRST($list) will evaluate to the string “Z”.

ARRAY_LAST

Definition: ARRAY_LAST(Array $list)

Equivalent to ARRAY_INDEX($list, ARRAY_LENGTH($list) – 1)

In this example:

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ARRAY_LAST($list) will result in the string “W”.

ARRAY_TAKE

Definition: ARRAY_TAKE(Array $list, Number $numberOfItems)

This function will extract the first $numberOfItems elements from the given array, and put them into a new (shorter) array.

For this example:

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Index Result
ARRAY_TAKE($list, 1) [“Z”]
ARRAY_TAKE ($list, 2) [“Z”, “Y”]
ARRAY_TAKE ($list, 3) [“Z”, “Y”, “X”]
ARRAY_TAKE ($list, 4) [“Z”, “Y”, “X”, “W”]

 

ARRAY_SKIP

Definition: ARRAY_SKIP(Array $list, Number $numberOfItems)

This function will skip $numberOfItems elements from the given array, and keep the rest. The remaining element will be put into a new (shorter) array.

For this example:

Index Result
ARRAY_SKIP($list, 1) [“Y”, “X”, “W”]
ARRAY_SKIP($list, 2) [“X”, “W”]
ARRAY_SKIP($list, 3) [“W”]
ARRAY_SKIP($list, 4) []

ARRAY_SLICE

ARRAY_SKIP(Array $list, Number $startAt, Number $numberOfItems)

This function combines ARRAY_SKIP and ARRAY_TAKE into a single function. The function will:

  • Start at$startAt (1-based)
  • Keep the next $numberOfItemsToKeep
  • Put these remaining elements into a new (shorter) array and return them

For this example:

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Index Result
ARRAY_SLICE($list, 1, 2) [“Z”, “Y”]
ARRAY_SLICE ($list, 2, 2) [“Y”, “X”]
ARRAY_SLICE ($list, 3, 1) [“X”]

 

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