tech.ml.dataset.base — techascent/tech.ml.dataset 2.12

->>dataset clj

(->>dataset dataset)

(->>dataset options dataset)

Please see documentation of ->dataset. Options are the same.

->dataset clj

(->dataset dataset)

(->dataset dataset {:keys [table-name dataset-name] :as options})

Create a dataset from either csv/tsv or a sequence of maps.

• A String or InputStream will be interpreted as a file (or gzipped file if it ends with .gz) of tsv or csv data. The system will attempt to autodetect if this is csv or tsv and then engineering around detecting datatypes all of which can be overridden.
• A sequence of maps may be passed in in which case the first N maps are scanned in order to derive the column datatypes before the actual columns are created. Options: :table-name - set the name of the dataset (deprecated in favor of :dataset-name). :dataset-name - set the name of the dataset. :file-type - Override filetype discovery mechanism for strings or force a particular parser for an input stream. Note that arrow and parquet must have paths on disk and cannot currently load from input stream. Acceptible file types are: #{:csv :tsv :xlsx :xls :arrow :parquet}. :gzipped? - for file formats that support it, override autodetection and force creation of a gzipped input stream as opposed to a normal input stream. :column-whitelist - either sequence of string column names or sequence of column indices of columns to whitelist. :column-blacklist - either sequence of string column names or sequence of column indices of columns to blacklist. :num-rows - Number of rows to read :header-row? - Defaults to true, indicates the first row is a header. :key-fn - function to be applied to column names. Typical use is: :key-fn keyword. :separator - Add a character separator to the list of separators to auto-detect. :csv-parser - Implementation of univocity's AbstractParser to use. If not provided a default permissive parser is used. This way you parse anything that univocity supports (so flat files and such). :bad-row-policy - One of three options: :skip, :error, :carry-on. Defaults to :carry-on. Some csv data has ragged rows and in this case we have several options . If the option is :carry-on then we either create a new column or add missing values for columns that had no data for that row. :skip-bad-rows? - Legacy option. Use :bad-row-policy. :max-chars-per-column - Defaults to 4096. Columns with more characters that this will result in an exception. :max-num-columns - Defaults to 8192. CSV,TSV files with more columns than this will fail to parse. For more information on this option, please visit: https://github.com/uniVocity/univocity-parsers/issues/301 :parser-fn -

• keyword - all columns parsed to this datatype
• ifn? - called with two arguments: (parser-fn column-name-or-idx column-data) - Return value must be implement tech.ml.dataset.parser.PColumnParser in which case that is used or can return nil in which case the default column parser is used.
• tuple - pair of [datatype parse-fn] in which case container of type [datatype] will be created. parse-fn can be one of: :relaxed? - data will be parsed such that parse failures of the standard parse functions do not stop the parsing process. :unparsed-values and :unparsed-indexes are available in the metadata of the column that tell you the values that failed to parse and their respective indexes. fn? - function from str-> one of #{:missing :parse-failure value}. Exceptions here always kill the parse process. :missing will get marked in the missing indexes, and :parse-failure will result in the index being added to missing, the unparsed the column's :unparsed-values and :unparsed-indexes will be updated. string? - for datetime types, this will turned into a DateTimeFormatter via DateTimeFormatter/ofPattern. DateTimeFormatter - use with the appropriate temporal parse static function to parse the value.
• map - the header-name-or-idx is used to lookup value. If not nil, then value can be any of the above options. Else the default column parser is used. :parser-scan-len - Length of initial column data used for parser-fn's datatype detection routine. Defaults to 100.

Returns a new dataset

->sort-by clj

(->sort-by dataset key-fn)

(->sort-by dataset key-fn compare-fn)

(->sort-by dataset key-fn compare-fn column-name-seq)

Version of sort-by used in -> statements common in dataflows

->sort-by-column clj

(->sort-by-column dataset colname)

(->sort-by-column dataset colname compare-fn)

sort-by-column used in -> dataflows

->string-reader clj

(->string-reader reader missing)

add-column clj

(add-column dataset column)

Add a new column. Error if name collision

add-or-update-column clj

(add-or-update-column dataset column)

(add-or-update-column dataset colname column)

If column exists, replace. Else append new column.

aggregate-by clj

(aggregate-by map-fn
              dataset
              &
              {:keys [column-name-seq numeric-aggregate-fn boolean-aggregate-fn
                      default-aggregate-fn count-column-name]
               :or {numeric-aggregate-fn dfn/reduce-+
                    boolean-aggregate-fn count-true
                    default-aggregate-fn first}})

Group the dataset by map-fn, then aggregate by the aggregate fn. Returns aggregated datatset. :aggregate-fn - passed a sequence of columns and must return a new column with the same number of entries as the count of the column sequences.

aggregate-by-column clj

(aggregate-by-column colname
                     dataset
                     &
                     {:keys [numeric-aggregate-fn boolean-aggregate-fn
                             default-aggregate-fn count-column-name]
                      :or {numeric-aggregate-fn dfn/reduce-+
                           boolean-aggregate-fn count-true
                           default-aggregate-fn first}})

Group the dataset by map-fn, then aggregate by the aggregate fn. Returns aggregated datatset. :aggregate-fn - passed a sequence of columns and must return a new column with the same number of entries as the count of the column sequences.

check-dataset-wrong-position clj

(check-dataset-wrong-position item)

column clj

(column dataset column-name)

Return the column or throw if it doesn't exist.

column-count clj

(column-count dataset)

column-name->column-map clj

(column-name->column-map datatypes)

clojure map of column-name->column

column-names clj

(column-names dataset)

In-order sequence of column names

columns clj

(columns dataset)

Return sequence of all columns in dataset.

columns-with-missing-seq clj

(columns-with-missing-seq dataset)

Return a sequence of: {:column-name column-name :missing-count missing-count } or nil of no columns are missing data.

concat clj

(concat dataset & datasets)

Concatenate datasets in place. Respects missing values. Datasets must all have the same columns. Result column datatypes will be a widening cast of the datatypes. Also see concat-copying as this may be faster in many situations.

concat-copying clj

(concat-copying dataset & datasets)

Concatenate datasets into a new dataset copying data. Respects missing values. Datasets must all have the same columns. Result column datatypes will be a widening cast of the datatypes.

concat-inplace clj

(concat-inplace dataset & datasets)

Concatenate datasets in place. Respects missing values. Datasets must all have the same columns. Result column datatypes will be a widening cast of the datatypes.

count-true clj

(count-true boolean-seq)

dataset->string clj

(dataset->string ds)

dataset-name clj

(dataset-name dataset)

drop-columns clj

(drop-columns dataset col-name-seq)

Same as remove-columns

drop-rows clj

(drop-rows dataset row-indexes)

Same as remove-rows.

ds-column-count clj

(ds-column-count dataset)

ds-concat clj

(ds-concat dataset & other-datasets)

Legacy method. Please see concat

ds-filter clj

(ds-filter predicate dataset & [column-name-seq])

Legacy method. Please see filter

ds-filter-column clj

(ds-filter-column predicate colname dataset)

Legacy method. Please see filter-column

ds-group-by clj

(ds-group-by key-fn dataset & [column-name-seq])

Legacy method. Please see group-by

ds-group-by-column clj

(ds-group-by-column colname dataset)

Legacy method. Please see group-by-column

ds-row-count clj

(ds-row-count dataset)

ds-sort-by clj

(ds-sort-by key-fn dataset)

(ds-sort-by key-fn compare-fn dataset)

(ds-sort-by key-fn compare-fn column-name-seq dataset)

Legacy method. Please see sort-by

ds-sort-by-column clj

(ds-sort-by-column colname dataset)

(ds-sort-by-column colname compare-fn dataset)

Legacy method. Please see sort by column.

ds-take-nth clj

(ds-take-nth n-val dataset)

Legacy method. Please see take-nth

ensure-array-backed clj

(ensure-array-backed ds)

(ensure-array-backed ds {:keys [unpack?] :or {unpack? true}})

Ensure the column data in the dataset is stored in pure java arrays. This is sometimes necessary for interop with other libraries and this operation will force any lazy computations to complete. This also clears the missing set for each column and writes the missing values to the new arrays.

Columns that are already array backed and that have no missing values are not changed and retuned.

The postcondition is that dtype/->array will return a java array in the appropriate datatype for each column.

options - :unpack? - unpack packed datetime types. Defaults to true

filter clj

(filter predicate dataset)

(filter predicate column-name-seq dataset)

dataset->dataset transformation. Predicate is passed a map of colname->column-value.

filter-column clj

(filter-column predicate colname dataset)

Filter a given column by a predicate. Predicate is passed column values. truthy values are kept. Returns a dataset.

from-prototype clj

(from-prototype dataset table-name column-seq)

Create a new dataset that is the same type as this one but with a potentially different table name and column sequence. Take care that the columns are all of the correct type.

group-by clj

(group-by key-fn dataset)

(group-by key-fn column-name-seq dataset)

Produce a map of key-fn-value->dataset. key-fn is a function taking a map of colname->column-value. Selecting which columns are used in the key-fn using column-name-seq is optional but will greatly improve performance.

group-by->indexes clj

(group-by->indexes key-fn dataset)

(group-by->indexes key-fn column-name-seq dataset)

group-by-column clj

(group-by-column colname dataset)

Return a map of column-value->dataset.

group-by-column->indexes clj

(group-by-column->indexes colname dataset)

has-column? clj

(has-column? dataset column-name)

index-value-seq clj

(index-value-seq dataset & [reader-options])

Get a sequence of tuples: [idx col-value-vec]

Values are in order of column-name-seq. Duplicate names are allowed and result in duplicate values.

mapseq-reader clj

(mapseq-reader dataset)

(mapseq-reader dataset options)

Return a reader that produces a map of column-name->column-value

Options: :missing-nil? - Default to true - Substitute nil in for missing values to make missing value detection downstream to be column datatype independent.

maybe-column clj

(maybe-column dataset column-name)

Return either column if exists or nil.

metadata clj

(metadata dataset)

missing clj

(missing dataset)

new-column clj

(new-column dataset column-name values)

Create a new column from some values

order-column-names clj

(order-column-names dataset colname-seq)

Order a sequence of columns names so they match the order in the original dataset. Missing columns are placed last.

remove-column clj

(remove-column dataset col-name)

Fails quietly

remove-columns clj

(remove-columns dataset colname-seq)

Same as drop-columns

remove-rows clj

(remove-rows dataset row-indexes)

Same as drop-rows.

rename-columns clj

(rename-columns dataset colname-map)

Rename columns using a map. Does not reorder columns.

row-count clj

(row-count dataset)

select clj

(select dataset colname-seq index-seq)

Reorder/trim dataset according to this sequence of indexes. Returns a new dataset. colname-seq - one of:

• :all - all the columns
• sequence of column names - those columns in that order.
• implementation of java.util.Map - column order is dictate by map iteration order selected columns are subsequently named after the corresponding value in the map. similar to rename-columns except this trims the result to be only the columns in the map. index-seq - either keyword :all or list of indexes. May contain duplicates.

select-columns clj

(select-columns dataset col-name-seq)

select-rows clj

(select-rows dataset row-indexes)

set-dataset-name clj

(set-dataset-name dataset ds-name)

set-metadata clj

(set-metadata dataset meta-map)

sort-by clj

(sort-by key-fn dataset)

(sort-by key-fn compare-fn dataset)

(sort-by key-fn compare-fn column-name-seq dataset)

Sort a dataset by a key-fn and compare-fn.

sort-by-column clj

(sort-by-column colname dataset)

(sort-by-column colname compare-fn dataset)

Sort a dataset by a given column using the given compare fn.

str->file-info clj

(str->file-info file-str)

supported-column-stats clj

(supported-column-stats dataset)

Return the set of natively supported stats for the dataset. This must be at least #{:mean :variance :median :skew}.

take-nth clj

(take-nth n-val dataset)

unique-by clj

(unique-by map-fn dataset)

(unique-by map-fn
           {:keys [column-name-seq keep-fn]
            :or {keep-fn (fn* [p1__38868# p2__38867#] (first p2__38867#))}
            :as _options}
           dataset)

Map-fn function gets passed map for each row, rows are grouped by the return value. Keep-fn is used to decide the index to keep.

:keep-fn - Function from key,idx-seq->idx. Defaults to #(first %2).

unique-by-column clj

(unique-by-column colname dataset)

(unique-by-column colname
                  {:keys [keep-fn]
                   :or {keep-fn (fn* [p1__38881# p2__38880#]
                                     (first p2__38880#))}
                   :as _options}
                  dataset)

Map-fn function gets passed map for each row, rows are grouped by the return value. Keep-fn is used to decide the index to keep.

:keep-fn - Function from key, idx-seq->idx. Defaults to #(first %2).

unordered-select clj

(unordered-select dataset colname-seq index-seq)

Perform a selection but use the order of the columns in the existing table; do not reorder the columns based on colname-seq. Useful when doing selection based on sets or persistent hash maps.

update-column clj

(update-column dataset col-name update-fn)

Update a column returning a new dataset. update-fn is a column->column transformation. Error if column does not exist.

update-columns clj

(update-columns dataset column-name-seq update-fn)

Update a sequence of columns.

value-reader clj

(value-reader dataset)

(value-reader dataset options)

Return a reader that produces a reader of column values per index. Options: :missing-nil? - Default to true - Substitute nil in for missing values to make missing value detection downstream to be column datatype independent.

wrap-stream-fn clj

(wrap-stream-fn dataset gzipped? open-fn)

write-csv! clj

(write-csv! ds output)

(write-csv! ds output options)

Write a dataset to a tsv or csv output stream. Closes output if a stream is passed in. File output format will be inferred if output is a string -

• .csv, .tsv - switches between tsv, csv. Tsv is the default.
• *.gz - write to a gzipped stream. At this time writing to json is not supported. options - :separator - in case output isn't a string, you can use either , or \tab to switch between csv or tsv output respectively.