JSONL-Tutorial: JSONL-Dateien erstellen, lesen & konvertieren

import json

with open("data.jsonl", "r", encoding="utf-8") as f:
    for line_number, line in enumerate(f, 1):
        line = line.strip()
        if not line:
            continue  # skip empty lines
        record = json.loads(line)
        print(f"Line {line_number}: {record['name']} - {record['role']}")

import { createReadStream } from 'fs';
import { createInterface } from 'readline';

const rl = createInterface({
  input: createReadStream('data.jsonl', 'utf-8'),
});

let lineNumber = 0;
for await (const line of rl) {
  if (!line.trim()) continue; // skip empty lines
  lineNumber++;
  const record = JSON.parse(line);
  console.log(`Line ${lineNumber}: ${record.name} - ${record.role}`);
}

# Erste 10 Zeilen anzeigen
head -n 10 data.jsonl

# Gesamtzahl der Datensätze zählen
wc -l data.jsonl

# Jede Zeile mit jq schön drucken
cat data.jsonl | jq .

# Datensätze filtern, wo role "engineer" ist
cat data.jsonl | jq 'select(.role == "engineer")'

# Nur das Name-Feld extrahieren
cat data.jsonl | jq -r '.name'

# Nach Zeilen suchen, die ein Schlüsselwort enthalten
grep '"Alice"' data.jsonl

import csv
import json

with open("data.csv", "r", encoding="utf-8") as csv_file:
    reader = csv.DictReader(csv_file)
    with open("data.jsonl", "w", encoding="utf-8") as jsonl_file:
        for row in reader:
            jsonl_file.write(json.dumps(row, ensure_ascii=False) + "\n")

print("Converted CSV to JSONL successfully")

import { readFileSync, writeFileSync } from 'fs';

const csv = readFileSync('data.csv', 'utf-8');
const lines = csv.trim().split('\n');
const headers = lines[0].split(',');

const jsonl = lines.slice(1).map(line => {
  const values = line.split(',');
  const obj = {'};
  headers.forEach((h, i) => obj[h.trim()] = values[i]?.trim());
  return JSON.stringify(obj);
}).join('\n');

writeFileSync('data.jsonl', jsonl + '\n', 'utf-8');
console.log('Converted CSV to JSONL successfully');