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CSV Column Selection
CSV column selection extracts specific columns from a CSV file, discarding the rest. This is useful when working with large datasets that have many columns but you only need a subset for analysis or import. It's a fundamental data transformation operation in ETL (Extract, Transform, Load) pipelines.
CSV Structure
Text
id,name,email,age,city,country
1,Alice,alice@example.com,30,New York,US
2,Bob,bob@example.com,25,London,UK
3,Carol,carol@example.com,35,Paris,FR
# Select only: id, name, email
id,name,email
1,Alice,alice@example.com
2,Bob,bob@example.com
3,Carol,carol@example.comColumn Selection in JavaScript
JavaScript
function selectCsvColumns(csvText, columns) {
const lines = csvText.trim().split('
');
const headers = lines[0].split(',').map(h => h.trim());
// Find indices of selected columns
const indices = columns.map(col => {
const idx = headers.indexOf(col);
if (idx === -1) throw new Error(`Column not found: ${col}`);
return idx;
});
return lines.map(line => {
const cells = line.split(',');
return indices.map(i => cells[i] ?? '').join(',');
}).join('
');
}
const csv = `id,name,email,age
1,Alice,alice@example.com,30
2,Bob,bob@example.com,25`;
console.log(selectCsvColumns(csv, ['id', 'name']));