frontend/node_modules/apache-arrow/compute/dataframe.mjs

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.
import { Table } from '../table';
import { IntVector } from '../vector/int';
import { Field, Schema } from '../schema';
import { Col } from './predicate';
import { RecordBatch } from '../recordbatch';
import { DataType } from '../type';
Table.prototype.countBy = function (name) { return new DataFrame(this.chunks).countBy(name); };
Table.prototype.scan = function (next, bind) { return new DataFrame(this.chunks).scan(next, bind); };
Table.prototype.scanReverse = function (next, bind) { return new DataFrame(this.chunks).scanReverse(next, bind); };
Table.prototype.filter = function (predicate) { return new DataFrame(this.chunks).filter(predicate); };
export class DataFrame extends Table {
    filter(predicate) {
        return new FilteredDataFrame(this.chunks, predicate);
    }
    scan(next, bind) {
        const batches = this.chunks, numBatches = batches.length;
        for (let batchIndex = -1; ++batchIndex < numBatches;) {
            // load batches
            const batch = batches[batchIndex];
            if (bind) {
                bind(batch);
            }
            // yield all indices
            for (let index = -1, numRows = batch.length; ++index < numRows;) {
                next(index, batch);
            }
        }
    }
    scanReverse(next, bind) {
        const batches = this.chunks, numBatches = batches.length;
        for (let batchIndex = numBatches; --batchIndex >= 0;) {
            // load batches
            const batch = batches[batchIndex];
            if (bind) {
                bind(batch);
            }
            // yield all indices
            for (let index = batch.length; --index >= 0;) {
                next(index, batch);
            }
        }
    }
    countBy(name) {
        const batches = this.chunks, numBatches = batches.length;
        const count_by = typeof name === 'string' ? new Col(name) : name;
        // Assume that all dictionary batches are deltas, which means that the
        // last record batch has the most complete dictionary
        count_by.bind(batches[numBatches - 1]);
        const vector = count_by.vector;
        if (!DataType.isDictionary(vector.type)) {
            throw new Error('countBy currently only supports dictionary-encoded columns');
        }
        const countByteLength = Math.ceil(Math.log(vector.length) / Math.log(256));
        const CountsArrayType = countByteLength == 4 ? Uint32Array :
            countByteLength >= 2 ? Uint16Array : Uint8Array;
        const counts = new CountsArrayType(vector.dictionary.length);
        for (let batchIndex = -1; ++batchIndex < numBatches;) {
            // load batches
            const batch = batches[batchIndex];
            // rebind the countBy Col
            count_by.bind(batch);
            const keys = count_by.vector.indices;
            // yield all indices
            for (let index = -1, numRows = batch.length; ++index < numRows;) {
                let key = keys.get(index);
                if (key !== null) {
                    counts[key]++;
                }
            }
        }
        return new CountByResult(vector.dictionary, IntVector.from(counts));
    }
}
/** @ignore */
export class CountByResult extends Table {
    constructor(values, counts) {
        const schema = new Schema([
            new Field('values', values.type),
            new Field('counts', counts.type)
        ]);
        super(new RecordBatch(schema, counts.length, [values, counts]));
    }
    toJSON() {
        const values = this.getColumnAt(0);
        const counts = this.getColumnAt(1);
        const result = {};
        for (let i = -1; ++i < this.length;) {
            result[values.get(i)] = counts.get(i);
        }
        return result;
    }
}
/** @ignore */
export class FilteredDataFrame extends DataFrame {
    constructor(batches, predicate) {
        super(batches);
        this._predicate = predicate;
    }
    scan(next, bind) {
        // inlined version of this:
        // this.parent.scan((idx, columns) => {
        //     if (this.predicate(idx, columns)) next(idx, columns);
        // });
        const batches = this._chunks;
        const numBatches = batches.length;
        for (let batchIndex = -1; ++batchIndex < numBatches;) {
            // load batches
            const batch = batches[batchIndex];
            const predicate = this._predicate.bind(batch);
            let isBound = false;
            // yield all indices
            for (let index = -1, numRows = batch.length; ++index < numRows;) {
                if (predicate(index, batch)) {
                    // bind batches lazily - if predicate doesn't match anything
                    // in the batch we don't need to call bind on the batch
                    if (bind && !isBound) {
                        bind(batch);
                        isBound = true;
                    }
                    next(index, batch);
                }
            }
        }
    }
    scanReverse(next, bind) {
        const batches = this._chunks;
        const numBatches = batches.length;
        for (let batchIndex = numBatches; --batchIndex >= 0;) {
            // load batches
            const batch = batches[batchIndex];
            const predicate = this._predicate.bind(batch);
            let isBound = false;
            // yield all indices
            for (let index = batch.length; --index >= 0;) {
                if (predicate(index, batch)) {
                    // bind batches lazily - if predicate doesn't match anything
                    // in the batch we don't need to call bind on the batch
                    if (bind && !isBound) {
                        bind(batch);
                        isBound = true;
                    }
                    next(index, batch);
                }
            }
        }
    }
    count() {
        // inlined version of this:
        // let sum = 0;
        // this.parent.scan((idx, columns) => {
        //     if (this.predicate(idx, columns)) ++sum;
        // });
        // return sum;
        let sum = 0;
        const batches = this._chunks;
        const numBatches = batches.length;
        for (let batchIndex = -1; ++batchIndex < numBatches;) {
            // load batches
            const batch = batches[batchIndex];
            const predicate = this._predicate.bind(batch);
            // yield all indices
            for (let index = -1, numRows = batch.length; ++index < numRows;) {
                if (predicate(index, batch)) {
                    ++sum;
                }
            }
        }
        return sum;
    }
    *[Symbol.iterator]() {
        // inlined version of this:
        // this.parent.scan((idx, columns) => {
        //     if (this.predicate(idx, columns)) next(idx, columns);
        // });
        const batches = this._chunks;
        const numBatches = batches.length;
        for (let batchIndex = -1; ++batchIndex < numBatches;) {
            // load batches
            const batch = batches[batchIndex];
            // TODO: bind batches lazily
            // If predicate doesn't match anything in the batch we don't need
            // to bind the callback
            const predicate = this._predicate.bind(batch);
            // yield all indices
            for (let index = -1, numRows = batch.length; ++index < numRows;) {
                if (predicate(index, batch)) {
                    yield batch.get(index);
                }
            }
        }
    }
    filter(predicate) {
        return new FilteredDataFrame(this._chunks, this._predicate.and(predicate));
    }
    countBy(name) {
        const batches = this._chunks, numBatches = batches.length;
        const count_by = typeof name === 'string' ? new Col(name) : name;
        // Assume that all dictionary batches are deltas, which means that the
        // last record batch has the most complete dictionary
        count_by.bind(batches[numBatches - 1]);
        const vector = count_by.vector;
        if (!DataType.isDictionary(vector.type)) {
            throw new Error('countBy currently only supports dictionary-encoded columns');
        }
        const countByteLength = Math.ceil(Math.log(vector.length) / Math.log(256));
        const CountsArrayType = countByteLength == 4 ? Uint32Array :
            countByteLength >= 2 ? Uint16Array : Uint8Array;
        const counts = new CountsArrayType(vector.dictionary.length);
        for (let batchIndex = -1; ++batchIndex < numBatches;) {
            // load batches
            const batch = batches[batchIndex];
            const predicate = this._predicate.bind(batch);
            // rebind the countBy Col
            count_by.bind(batch);
            const keys = count_by.vector.indices;
            // yield all indices
            for (let index = -1, numRows = batch.length; ++index < numRows;) {
                let key = keys.get(index);
                if (key !== null && predicate(index, batch)) {
                    counts[key]++;
                }
            }
        }
        return new CountByResult(vector.dictionary, IntVector.from(counts));
    }
}

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