/
rows.clj
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/
rows.clj
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(ns tablecloth.api.rows
(:refer-clojure :exclude [shuffle rand-nth first last])
(:require [tech.v3.dataset :as ds]
[tech.v3.datatype.argops :as aop]
[tablecloth.api.utils :refer [iterable-sequence? rank column-names]]
[tablecloth.api.dataset :refer [rows]]
[tablecloth.api.columns :refer [add-columns select-columns]]
[tablecloth.api.group-by :refer [grouped? process-group-data]]))
(defn- find-indexes-from-seq
"Find row indexes based on true/false values or indexes"
[ds rows-selector]
(if (number? (clojure.core/first rows-selector))
rows-selector
(->> rows-selector
(take (ds/row-count ds))
(aop/argfilter identity))))
(defn- find-indexes-from-fn
"Filter rows"
[ds rows-selector selected-keys]
(->> (or selected-keys :all)
(ds/select-columns ds)
(ds/mapseq-reader)
(aop/argfilter rows-selector)))
(defn- find-indexes
([ds rows-selector] (find-indexes ds rows-selector nil))
([ds rows-selector selected-keys]
(cond
(number? rows-selector) [(long rows-selector)]
(iterable-sequence? rows-selector) (find-indexes-from-seq ds rows-selector)
(fn? rows-selector) (find-indexes-from-fn ds rows-selector selected-keys))))
(defn- select-or-drop-rows
"Select or drop rows."
([f ds rows-selector] (select-or-drop-rows f ds rows-selector nil))
([f ds rows-selector {:keys [select-keys pre result-type parallel?]}]
(let [selected-keys (column-names ds select-keys)]
(if (grouped? ds)
(let [mapper (if parallel? pmap map)
pre-ds (mapper #(add-columns % pre) (ds :data))
indices (mapper #(find-indexes % rows-selector selected-keys) pre-ds)]
(if (= result-type :as-indexes)
(mapper seq indices)
(ds/add-or-update-column ds :data (mapper #(select-or-drop-rows f %1 %2) (ds :data) indices))))
(let [indices (find-indexes (add-columns ds pre) rows-selector selected-keys)]
(if (= result-type :as-indexes)
(seq indices)
(f ds indices)))))))
(defn- select-or-drop-rows-docstring
[op]
(str op " rows using:
- row id
- seq of row ids
- seq of true/false
- fn with predicate"))
(def ^{:doc (select-or-drop-rows-docstring "Select")
:arglists '([ds rows-selector] [ds rows-selector {:keys [select-keys pre result-type parallel?]}])}
select-rows (partial select-or-drop-rows ds/select-rows))
(def ^{:doc (select-or-drop-rows-docstring "Drop")
:arglists '([ds rows-selector] [ds rows-selector {:keys [select-keys pre result-type parallel?]}])}
drop-rows (partial select-or-drop-rows ds/drop-rows))
;;
(defn head
([ds] (head ds 5))
([ds n]
(if (grouped? ds)
(process-group-data ds #(ds/head % n))
(ds/head ds n))))
(defn tail
([ds] (tail ds 5))
([ds n]
(if (grouped? ds)
(process-group-data ds #(ds/tail % n))
(ds/tail ds n))))
(defn- shuffle-seq
[seq rng]
(let [^java.util.Collection s seq
ar (java.util.ArrayList. s)]
(if rng
(java.util.Collections/shuffle ar rng)
(java.util.Collections/shuffle ar))
ar))
(defn- shuffle-with-rng
[ds rng]
(ds/select-rows ds (shuffle-seq (range (ds/row-count ds)) rng)))
(defn shuffle
([ds] (shuffle ds nil))
([ds {:keys [seed]}]
(let [rng (when seed (java.util.Random. seed))]
(if (grouped? ds)
(process-group-data ds #(shuffle-with-rng % rng))
(shuffle-with-rng ds rng)))))
(defn- get-random-long
^long [^long cnt ^java.util.Random rng]
(if rng
(mod (.nextLong rng) cnt)
(long (rand cnt))))
(defn- process-random
[ds repeat? n rng]
(let [cnt (ds/row-count ds)
n (if (number? n) n cnt)
idxs (if repeat?
(repeatedly n #(get-random-long cnt rng))
(take (min cnt n) (shuffle-seq (range cnt) rng)))]
(ds/select-rows ds idxs)))
(defn random
([ds] (random ds (ds/row-count ds)))
([ds n] (random ds n nil))
([ds n {:keys [repeat? seed]
:or {repeat? true}}]
(let [rng (when seed (java.util.Random. seed))]
(if (grouped? ds)
(process-group-data ds #(process-random % repeat? n rng))
(process-random ds repeat? n rng)))))
(defn- process-rand-nth
[ds rng]
(ds/select-rows ds (get-random-long (ds/row-count ds) rng)))
(defn rand-nth
([ds] (rand-nth ds nil))
([ds {:keys [seed]}]
(let [rng (when seed (java.util.Random. seed))]
(if (grouped? ds)
(process-group-data ds #(process-rand-nth % rng))
(process-rand-nth ds rng)))))
(defn first
[ds]
(if (grouped? ds)
(process-group-data ds #(ds/select-rows % [0]))
(ds/select-rows ds [0])))
(defn last
[ds]
(if (grouped? ds)
(process-group-data ds last)
(let [idx (dec (ds/row-count ds))]
(ds/select-rows ds [idx]))))
(defn- rank-by-process
[ds rank-fn rank-predicate]
(->> ds
(rank-fn)
(map rank-predicate)
(select-rows ds)))
(defn by-rank
"Select rows using `rank` on a column, ties are resolved using `:dense` method.
See [R docs](https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/rank).
Rank uses 0 based indexing.
Possible `:ties` strategies: `:average`, `:first`, `:last`, `:random`, `:min`, `:max`, `:dense`.
`:dense` is the same as in `data.table::frank` from R
`:desc?` set to true (default) order descending before calculating rank"
([ds columns-selector rank-predicate] (by-rank ds columns-selector rank-predicate nil))
([ds columns-selector rank-predicate {:keys [desc? ties]
:or {desc? true ties :dense}}]
(let [col-names (column-names (if (grouped? ds)
(clojure.core/first (ds :data))
ds) columns-selector)
rank-fn (if (= 1 (count col-names))
(let [n (clojure.core/first col-names)]
#(rank (% n) ties desc?))
#(rank (->> (-> (select-columns % col-names)
(rows :as-seq))
(map vec)) ties desc?))]
(if (grouped? ds)
(process-group-data ds #(rank-by-process % rank-fn rank-predicate))
(rank-by-process ds rank-fn rank-predicate)))))