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content-type: "page"
title: "seq Module"
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{@ _defs_.md || 0 @}

{#sig||/||dget#}

{#sig||?||dhas?#}

{#sig||%||dset#}

{#op||all?||{{q1}} {{q2}}||{{b}}||
Applies predicate {{q2}} to each element of {{q1}} and returns {{t}} if all elements of {{q1}} satisfy predicate {{q2}}, {{f}} otherwise. #}

{#op||any?||{{q1}} {{q2}}||{{b}}||
Applies predicate {{q2}} to each element of {{q1}} and returns {{t}} if at least one element of {{q1}} satisfies predicate {{q2}}, {{f}} otherwise. #}

{#op||append||{{any}} {{q}}||({{a0p}} {{any}})||
Returns a new quotation containing the contents of {{q}} with {{any}} appended. #}

{#op||get||{{q}} {{i}}||{{any}}||
Returns the _n^th_ element of {{q}} (zero-based).#}

{#op||concat||{{q1}} {{q2}}||{{q3}}||
Concatenates {{q1}} with {{q2}}. #}

{#op||ddel||{{d1}} {{sl}}||{{d2}}||
Returns a copy of {{d1}} without the element with key {{sl}}. #}

{#op||dget||{{d}} {{sl}}||{{any}}||
Returns the value of key {{sl}} from dictionary {{d}}. #}

{#op||dhas?||{{d}} {{sl}}||{{b}}||
> Returns {{t}} if dictionary {{d}} contains the key {{sl}}, {{f}} otherwise.
> 
> > %sidebar%
> > Example
> >  
> > The following program returns {{t}}:
> > 
> >     (("a1" true) ("a2" "aaa") ("a3" false)) 'a2 dhas?
 #}

{#op||dkeys||{{d}}||({{s}}{{0p}})||
Returns a quotation containing all the keys of dictionary {{d}}. #}

{#op||dpick||{{d1}} {{q}}||{{d2}}||
> Returns a new dictionary {{d2}} containing the elements of {{d1}} whose keys are included in {{q}}.
> 
> > %sidebar%
> > Example
> >  
> > The following program returns `(("a" 4) ("d" 7))`:
> > 
> >     (("q" 5) ("a" 4) ("c" 6) ("d" 7)) ("a" "d") dpick
 #}

{#op||dset||{{d1}} {{any}} {{sl}}||{{d2}}||
Sets the value of the {{sl}} of {{d1}}  to {{any}}, and returns the modified copy of the dictionary {{d2}}. #}

{#op||dsort||{{d1}}||{{d2}}||
> Returns a new dictionary {{d2}} containing all elements of {{d1}} sorted by key in ascending order.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `(("a" 342) ("b" true) ("c" -4) ("d" 22))` on the stack:
> > 
> >     (("b" true) ("d" 22) ("c" -4) ("a" 342)) dsort#}

{#op||dvalues||{{d}}||({{a0p}})||
Returns a quotation containing all the values of dictionary {{d}}. #}

{#op||filter||{{q1}} {{q2}}||{{q3}}||
> Returns a new quotation {{q3}} containing all elements of {{q1}} that satisfy predicate {{q2}}.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `(2 6 8 12)` on the stack:
> > 
> >     (1 37 34 2 6 8 12 21) 
> >     (dup 20 < swap even? and) filter #}

{#op||find||{{q1}} {{q2}}||{{i}}||
> Returns the index of the first element within {{q1}} that satisfies predicate {{q2}}.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `3` on the stack:
> > 
> >     (1 2 4 8 16) 
> >     (5 >) find #}

{#op||first||{{q}}||{{any}}||
Returns the first element of {{q}}. #}

{#op||flatten||{{q1}}||{{q2}}||
> Flattens all quotations within {{q1}} and returns the resulting sequence {{q2}}.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `(1 2 3 4 5 6 7 8)` on the stack:
> > 
> >     (1 (2 3 4) 5 (6 7) 8) 
> >     flatten #}

{#op||harvest||{{q1}}||{{q2}}||
> Creates a new quotation {{q2}} containing all elements of {{q1}} except for empty quotations.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `(1 2 3)` on the stack:
> > 
> >     (1 () () () 2 () 3) 
> >     harvest #}

{#op||in?||{{q}} {{any}}||{{b}}||
Returns {{t}} if {{any}} is contained in {{q}}, {{f}} otherwise.#}

{#op||insert||{{q1}} {{any}} {{i}}||{{q2}}||
Inserts {{any}} as the value of the _n^th_ element {{q1}} (zero-based), and returns the modified copy of the quotation {{q2}}. #}

{#op||last||{{q}}||{{any}}||
Returns the last element of {{q}}. #}

{#op||map||{{q1}} {{q2}}||{{q3}}||
Returns a new quotation {{q3}} obtained by applying {{q2}} to each element of {{q1}}.#}

{#op||map-reduce||{{q1}} {{q2}} {{q3}}||{{i}}||
> Applies {{q2}} (map) to each element of {{q1}} and then applies {{q3}} (reduce) to each successive element of {{q1}}. {{q1}} must have at least one element.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `35` on the stack:
> > 
> >     (1 3 5) 
> >     (dup *) (+) map-reduce #}

{#op||partition||{{q1}} {{q2}}||{{q3}} {{q4}}||
> Partitions {{q1}} into two quotations: {{q3}} contains all elements of {{q1}} that satisfy predicate {{q2}}, {{q4}} all the others.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `(1 2 3) (2 4 6)` on the stack:
> > 
> >     (1 2 3 4 5 6) 
> >     (odd?) partition #}

{#op||prepend||{{any}} {{q}}||({{any}} {{a0p}})||
Returns a new quotation containing the contents of {{q}} with {{any}} prepended. #}

{#op||quote-map||{{q1}}||{{q2}}||
Returns a new quotation {{q2}} obtained by quoting each element of {{q1}}.#}

{#op||reduce||{{q1}} {{any}} {{q2}}||{{i}}||
> Combines each successive element of {{q1}} using {{q2}}. On the first iteration, the first two inputs processed by {{q2}} are {{any}} and the first element of {{q1}}.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `120` on the stack:
> > 
> >     (1 2 3 4 5) 
> >     1 (*) reduce #}

{#op||reject||{{q1}} {{q2}}||{{q3}}||
Returns a new quotatios {{q3}} including all elements of {{q1}} that do not satisfy predicate {{q2}} (i.e. the opposite of `filter`)#}

{#op||remove||{{q1}} {{i}}||{{q2}}||
Returns the _n^th_ element of {{q1}} (zero-based), and returns the modified copy of the quotation {{q2}}.#}

{#op||rest||{{q1}}||{{q2}}||
Returns a new quotation {{q2}} containing all elements of {{q1}} quotation except for the first. #}

{#op||reverse||{{q1}}||{{q2}}||
Returns a new quotation {{q2}} containing all elements of {{q1}} in reverse order. #}

{#op||set||{{q1}} {{any}} {{i}}||{{q2}}||
Sets the value of the _n^th_ element {{q1}} (zero-based) to {{any}}, and returns the modified copy of the quotation {{q2}}. #}

{#op||shorten||{{q1}} {{i}}||{{q2}}||
Returns a quotation {{q2}} containing the first _n_ values of the input quotation {{q1}}. #}

{#op||size||{{q}}||{{i}}||
Returns the length of {{q}}.#}

{#op||slice||{{q1}} {{i1}} {{i2}}||{{q2}}||
> Creates a new quotation {{q2}} obtaining by selecting all elements of {{q1}} between indexes {{i1}} and {{i2}}.
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `(3 4 5)` on the stack:
> > 
> >     (1 2 3 4 5 6) 
> >     2 4 slice #}

{#op||sort||{{q1}} {{q2}}||{{q3}}||
> Sorts all elements of {{q1}} according to predicate {{q2}}. 
> 
> > %sidebar%
> > Example
> > 
> > The following program leaves `(1 3 5 7 9 13 16)` on the stack:
> > 
> >     (1 9 5 13 16 3 7) '> sort #}