Each

C10 - initial

each (Sifts)
Type	Corrade progressive sift
Sift	`each`
Parameters	`integer`
Description	The `each` sift will return a strided list given a supplied number.
Last Changes	None

The each sift will return a strided list given a supplied number.

Arguments

Position	Type	Description	Example
`0`	an integer	return a strided list with the given stride number	`2`

Example

The following sift when added to a command will return each second element in the list starting and including the first zero-indexed element:

    "sift", wasListToCSV([
        "each", 2
    ]),

Effect on Returned Data

Given the input

data=a,1,b,2,c,3,d,4,e,5

the expected output is:

data=a,b,c,d,e

Notes

Formally, given a list $L$ of elements, the each sift will return the subset $L_{s} = \{ e | e = ip, \forall i : \mathbb{N} \mapsto \lbrack 0, n ) \mathtext{ and } p : \mathbb{N} \mapsto {N} \}$ where $n$ represents the length of the list $L$ , $i$ are indices of the list and $p$ is the stride. This may seem counter-intuitive for non-programmers since the selection is expected to start from $p$ ignoring indices that conventionally start at $0$ . That is, the selection formula for the subset $L_{s}$ is expected to be $e = ip + 1$ . In case the latter behaviour is desired, then an additional skip sift can be used to offset the start of the list such that the selection formula for the subset $L_{s}$ becomes $e = ip - (p - 1)$ .

For example, suppose that each second element in a list would have to be selected without accounting for zero-based indexed arrays or lists, then the sift would be:

    "sift", wasListToCSV([
        "skip", 1,
        "each", 2
    ]),

similarly, for each third element in a list:

    "sift", wasListToCSV([
        "skip", 2,
        "each", 3
    ]),

Table of Contents

Each

Arguments

Example

Effect on Returned Data

Notes