nth ( n seq -- elt )
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Vocabulary
sequences

Inputs

n	a non-negative integer
seq	a sequence

Outputs

elt	the element at the nth index

Generic word contract
Outputs the nth element of the sequence. Elements are numbered from zero, so the last element has an index one less than the length of the sequence. All sequences support this operation.

Errors
Throws a bounds-error if the index is negative, or greater than or equal to the length of the sequence.

Examples

USING: prettyprint sequences ; 1 { "a" "b" "c" } nth .
"b"

See also
?nth

Definition

IN: sequences

GENERIC: nth ( n seq -- elt ) flushable

Methods

USING: accessors grouping kernel math sequences ;

M: circular-clumps nth
    [ n>> over + ] [ seq>> ] bi <circular-slice> ; inline


USING: accessors kernel math quotations sequences ;

M: curried nth
    over 0 =
    [ nip obj>> literalize ] [ [ 1 - ] dip quot>> nth ] if ;


USING: accessors game.models.util kernel sequences ;

M: indexed-seq nth [ iseq>> nth ] keep dseq>> nth ; inline


USING: sequences sequences.modified ;

M: modified nth modified-nth ;


USING: accessors kernel sequences sequences.product
sequences.product.private ;

M: product-sequence nth
    [ lengths>> product-ns ] [ sequences>> product-nths ] bi ;


USING: sequences sequences.private ;

M: sequence nth bounds-check nth-unsafe ; inline


USING: accessors kernel sequences xml.data ;

M: tag nth [ children>> ] call \ nth execute ;


USING: accessors sequences tensors tensors.private ;

M: tensor nth num-index vec>> nth ;


USING: sequences ;

M: virtual-sequence nth virtual@ nth ; inline


USING: accessors kernel sequences xml.data ;

M: xml-chunk nth [ seq>> ] call \ nth execute ;


USING: accessors kernel sequences xml.data ;

M: xml nth [ body>> ] call \ nth execute ;