Merge pull request #3 from ccri/table-from-struct

Table from struct

Author: trxcllnt

js/perf/index.js

@@ -144,10 +144,10 @@ function createDataFrameDirectCountTest(table, column, test, value) {
  let numBatches = batches.length;
  for (let batchIndex = -1; ++batchIndex < numBatches;) {
  // load batches
- const { numRows, columns } = batches[batchIndex];
- const vector = columns[colidx];
+ const batch = batches[batchIndex];
+ const vector = batch.getChildAt(colidx);
  // yield all indices
- for (let index = -1; ++index < numRows;) {
+ for (let index = -1; ++index < batch.length;) {
  sum += (vector.get(index) >= value);
  }
  }
@@ -159,10 +159,10 @@ function createDataFrameDirectCountTest(table, column, test, value) {
  let numBatches = batches.length;
  for (let batchIndex = -1; ++batchIndex < numBatches;) {
  // load batches
- const { numRows, columns } = batches[batchIndex];
- const vector = columns[colidx];
+ const batch = batches[batchIndex];
+ const vector = batch.getChildAt(colidx);
  // yield all indices
- for (let index = -1; ++index < numRows;) {
+ for (let index = -1; ++index < batch.length;) {
  sum += (vector.get(index) === value);
  }
  }
@@ -173,7 +173,7 @@ function createDataFrameDirectCountTest(table, column, test, value) {
 
  return {
  async: true,
- name: `name: '${column}', length: ${table.numRows}, type: ${table.columns[colidx].type}, test: ${test}, value: ${value}\n`,
+ name: `name: '${column}', length: ${table.numRows}, type: ${table.getColumnAt(colidx).type}, test: ${test}, value: ${value}\n`,
  fn: op
  };
 }
@@ -183,7 +183,7 @@ function createDataFrameCountByTest(table, column) {
 
  return {
  async: true,
- name: `name: '${column}', length: ${table.numRows}, type: ${table.columns[colidx].type}\n`,
+ name: `name: '${column}', length: ${table.numRows}, type: ${table.getColumnAt(colidx).type}\n`,
  fn() {
  table.countBy(column);
  }
@@ -204,7 +204,7 @@ function createDataFrameFilterCountTest(table, column, test, value) {
 
  return {
  async: true,
- name: `name: '${column}', length: ${table.numRows}, type: ${table.columns[colidx].type}, test: ${test}, value: ${value}\n`,
+ name: `name: '${column}', length: ${table.numRows}, type: ${table.getColumnAt(colidx).type}, test: ${test}, value: ${value}\n`,
  fn() {
  df.count();
  }

js/src/table.ts

@@ -20,7 +20,8 @@ import { Col, Predicate } from './predicate';
 import { Schema, Field, Struct } from './type';
 import { read, readAsync } from './ipc/reader/arrow';
 import { isPromise, isAsyncIterable } from './util/compat';
-import { Vector, DictionaryVector, IntVector } from './vector';
+import { Vector, DictionaryVector, IntVector, StructVector } from './vector';
+import { ChunkedView } from './vector/chunked';
 
 export type NextFunc = (idx: number, cols: RecordBatch) => void;
 
@@ -61,6 +62,13 @@ export class Table implements DataFrame {
  }
  return Table.empty();
  }
+ static fromStruct(struct: StructVector) {
+ const schema = new Schema(struct.type.children);
+ const chunks = struct.view instanceof ChunkedView ?
+ (struct.view.childVectors as StructVector[]) :
+ [struct];
+ return new Table(chunks.map((chunk)=>new RecordBatch(schema, chunk.length, chunk.view.childData)));
+ }
 
  public readonly schema: Schema;
  public readonly length: number;