CSV Basics

CSV (Comma-Separated Values) is the lingua franca of tabular data. Conceptually trivial:

name,age,city
Alice,30,NYC
Bob,25,LA

Each line is a row; commas separate columns; the first row is often a header.

In practice CSV is shockingly inconsistent across tools:

• Excel uses ; in some locales (because comma is the decimal separator)
• Different line endings (\n vs \r\n vs \r)
• Different quote characters (" is standard but ' happens)
• Various escape rules

RFC 4180 standardized the format in 2005, but many parsers are lenient.

Required handling:

1. Field separators
2. Line endings
3. Quoted fields (with escaped quotes inside)
4. Empty fields
5. Numeric vs string fields (no type info — caller decides)