Load previously-saved data

scripts/concat-parquet

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+#!/usr/bin/env python3
+
+"""
+Concatenates multiple parquet files into a single parquet output
+"""
+
+import pyarrow as pa
+import pyarrow.parquet as pq
+import pandas as pd
+import sys
+import argparse
+
+parser = argparse.ArgumentParser(
+    prog="combine-parquet",
+    description=__doc__
+)
+
+parser.add_argument(
+    '-i', '--input',
+    nargs='*',
+    help=f'Input files'
+)
+
+parser.add_argument(
+    '-o', '--output',
+    help=f'Output files'
+)
+
+args = parser.parse_args()
+
+df = None
+
+for file in args.input:
+
+    part = pq.read_table(file).to_pandas()
+
+    if df is None:
+        df = part
+    else:
+        df = pd.concat([df, part], ignore_index=True)
+
+if df is not None:
+
+    table = pa.Table.from_pandas(df)
+    pq.write_table(table, args.output)