numbers as keys are somewhat accidentally supported because the tosym function
returns y if y can't be converted directly to symbols. The error handling was
meant to pass along symbols unchanged, but has same feature for numbers.
4 kvget 3 4 5 kv 3 2 $ 'abc'
ca
The dsLs that allow string description of dictionaries also support numeric
keys by using the gerund form of the dsL adverbs. the u form of the adverb
just processes/parses the right of ` in string (values section), while f`u
applies f to the key section, u to values section.
4 kvget ".`cut kvdsL ' 3 4 5 ` a bc g'
bc
What isn't supported is mixing numbers and symbols as keys. They can be mixed
as values because they will be autoboxed. Number keyed dictionaries embedded
in other dictionaries will be hard to access with "dsl paths", but forming the
path manually will give deep access.
('top';5) kvgetd 'top' kv < ".`cut kvdsL ' 3 4 5 ` a bc g'
g
('top'; 4) kvgetd ('top' kv < 4 5 kv > cut 'dd ee') kvsetd 'top' kv < ".`cut
kvdsL ' 3 4 5 ` a bc g'
dd
> tutorial
almost all functions (except kvdsL) are dyadic. In above examples cutting from
left the x v portions of x v y will provide the intermediate results of right
uncut expressions. kvtest has a series of function calls that provide examples
of all functions.
> function filtering values
G1 -: kvvals NB. values is just 1 {:: dictionary
G1 'top' kvget 'top' kv < ".`cut kvdsL ' 3 4 5 ` a bc g' NB. unwrap embedded
dict before getting deep values
a
bc
g
kvi is a function that will "filter" dictionary by index list x. kvdi deletes
by indexes.
so filtering by values by creating a hook with kvi~
functionThatEvaluatesIndexes
4 kvget (kvi~ ('b' I.@:= {."1)@:G1) ".`cut kvdsL ' 3 4 5 ` a bc g'
bc
kvvals 0 2 kvi ".`cut kvdsL ' 3 4 5 ` a bc g'
a
g
kvfilt and kvfiltall will filter dictionary by list of keys. The all version
returns duplicate keys if any. kvdel and kvdelall are "inverse filters" by
keys.
kvQ is a "query language" for inverted tables (when all keys in dictionary hold
a boxed table, representing 1 column per key)
> filter with predicates both for key and value?
doing them in sequence,
G1 'g' (] kvi~ I.@:(padstrmatch G1)) 4 kvdel ".`cut kvdsL ' 3 4 5 ` a bc g'
g
On Saturday, February 19, 2022, 04:33:59 a.m. EST, Pawel Jakubas
<[email protected]> wrote:
Hi Pascal,
Thanks for the release. Couple questions:
1. Can key be number, if not why not?
2. Any chance to add user friendly tutorial how to use every kv function
and what are consequences/peculiarities in such a way that one can by
copy-pasting get the same result and understand them?
3. What about function filtering values, maybe having filter with
predicates both for key and value?
Thanks,
Pawel
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