accumulate*! ( ... seq identity quot: ( ... prev elt -- ... next ) -- ... seq )

Factor handbook » The language » Collections » Sequence operations » Destructive sequence operations

Factor handbook » The language » Collections » Sequence operations » Destructive sequence operations

Prev: | accumulate! ( ... seq identity quot: ( ... prev elt -- ... next ) -- ... final seq ) |

Next: | change-nth ( ..a i seq quot: ( ..a elt -- ..b newelt ) -- ..b ) |

Vocabulary

sequences

Inputs

Outputs

Word description

Combines successive elements of the sequence using a binary operation, and outputs the original sequence of all results.

On the first iteration, the two inputs to the quotation are identity and the first element of the input sequence. On successive iterations, the first input is the result of the previous iteration, and the second input is the next element of the input sequence.

When given the empty sequence, outputs the same empty sequence.

Errors

Throws an error if the sequence is immutable, or the sequence cannot hold elements of the type output by quot.

Side effects

Modifies seq

Examples

Notes

May be named scan or prefix sum in other languages.

See also

accumulate, accumulate!, accumulate-as, accumulate*, accumulate*-as

Definition

sequences

Inputs

seq | a sequence |

identity | an object |

quot | a quotation with stack effect ( ... prev elt -- ... next ) |

Outputs

seq | a sequence |

Word description

Combines successive elements of the sequence using a binary operation, and outputs the original sequence of all results.

On the first iteration, the two inputs to the quotation are identity and the first element of the input sequence. On successive iterations, the first input is the result of the previous iteration, and the second input is the next element of the input sequence.

When given the empty sequence, outputs the same empty sequence.

Errors

Throws an error if the sequence is immutable, or the sequence cannot hold elements of the type output by quot.

Side effects

Modifies seq

Examples

USING: math prettyprint sequences ;
{ 2 2 2 2 2 } 0 [ + ] accumulate*! .

{ 2 4 6 8 10 }

{ 2 4 6 8 10 }

Notes

May be named scan or prefix sum in other languages.

See also

accumulate, accumulate!, accumulate-as, accumulate*, accumulate*-as

Definition

: accumulate*!

( ... seq identity quot: ( ... prev elt -- ... next ) -- ... seq )

(accumulate*) map! nip ; inline

( ... seq identity quot: ( ... prev elt -- ... next ) -- ... seq )

(accumulate*) map! nip ; inline