Comma-Separated Values (.csv)
RFC StandardComma-Separated Values (CSV) is a ubiquitous plain-text format for tabular data, where each line represents a data record and fields are separated by delimiter characters.
Teisenda formaadist XLSX formaati CSV
Tasuta XLSX -> CSV konverter brauseris. Teisenda faile koheselt oma seadmes.
Tihenda CSV võrgus
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Kontrolli ja metaandmed
Operatsioonisüsteemid ja failianalüsaatorid tuvastavad CSV faile, kontrollides algset binaarset baidijada:
Baidi-taseme päise allkiri (maagilised baidid)
Operatsioonisüsteemid ja failianalüsaatorid tuvastavad CSV faile, kontrollides algset binaarset baidijada:
HEX-ALLKIRI (NIHE 0):
Plain TextASCII-ESITUS: ASCII / UTF-8
Standardiseerimine: RFC 4180 / IETF
Tehnilised andmed
| Konteineri arhitektuur | Delimited flat text file representing tabular data rows and columns |
| Tihendamine | Gzip / Deflate achieves 85%-95% compression on repetitive tabular records |
| Baitide järjekord (Endianness) | UTF-8 text stream (optional UTF-8 BOM EF BB BF used by Excel) |
| Värviruumid | Not applicable |
| Kanalid ja struktuur | Row records delimited by CRLF with columns delimited by commas |
| Max mõõtmed | Unbounded; streamable to gigabytes without loading entire file in memory |
| Läbipaistvus | Not applicable |
| Voogedastus ja progressiivsus | Native line-by-line stream processing supported by all data pipelines |
Tehniline võrdlusmaatriks: CSV vs konkurendid
| Tehniline atribuut | CSV (Praegune) | Excel (XLSX) | Parquet | JSON |
|---|---|---|---|---|
| File Type | Plain text flat table | Zipped XML spreadsheet | Binary columnar storage | Hierarchical text |
| Multiple Sheets | No (single flat table only) | Yes (multiple workbooks and sheets) | Partition-based storage | Nested arrays and objects |
| Data Types | Untyped raw text | Typed cells, formulas, formatting | Strict binary column types | Primitive types (string, number, bool) |
| Big Data Analytics | Slow (requires reading every row linearly) | Not suitable for big data | Ultra-fast (column pruning & predicate pushdown) | Moderate |
Levinud riknemisvead ja heksataaste juhend
⚠️ Columns shift to the right or row counts do not match.
Juurpõhjus: A text field containing an unescaped comma without surrounding quotation marks.
Taastamine: RFC 4180 requires fields containing commas to be wrapped in double quotes: "Smith, John".
⚠️ Accented characters render as strange symbols (mojibake like é instead of é) in Excel.
Juurpõhjus: Excel opened a UTF-8 CSV assuming the legacy Windows ANSI/CP1252 character encoding.
Taastamine: Prepend the 3-byte UTF-8 Byte Order Mark (0xEF 0xBB 0xBF) to the beginning of the file.
Turvaanalüüs ja parsimisründevektorid
CSV files open directly in spreadsheet software like Excel and Google Sheets, exposing users to Formula Injection (CSV Injection) attacks.
Teadaolevad ründavektorid
- Formula Injection: Cells starting with '=', '+', '-', or '@' executing spreadsheet macros or DDE commands (e.g. '=cmd|' /C calc'!A0').
- Data exfiltration via HYPERLINK() formulas sending sensitive cell data to remote attacker servers upon click.
Kaitsealased parimad tavad: When exporting user data to CSV, prepend a single quote (') or tab to any cell starting with '=', '+', '-', or '@' to force plain text rendering in Excel.
Ajalooline taust ja verstapostid
Peamised eelised
- Maximum simplicity: readable in any text editor and importable into every database and spreadsheet.
- Extremely fast line-by-line streaming without building a full in-memory DOM.
- Minimal overhead: no verbose tag syntax or schema definitions.
Tehnilised piirangud ja puudused
- No standard data types: numbers, dates, booleans, and text are all stored as raw strings.
- No support for multiple sheets, cell formatting, formulas, or metadata.
- Delimiter conflicts (commas inside text, decimal commas in European locales) cause frequent parsing bugs.
Huvitavaid tehnilisi fakte
- In many European countries where commas are used as decimal points, semicolons (;) are used instead of commas as CSV separators.
- Microsoft Excel historically required a UTF-8 BOM (0xEF 0xBB 0xBF) to correctly display non-ASCII accented characters.
Korduma kippuvad tehnilised küsimused
What is RFC 4180?
RFC 4180 is the official IETF standard for CSV. It mandates that fields containing commas, line breaks, or double quotes must be enclosed in double quotes, and internal quotes must be escaped by doubling them ("").
Why do CSV files open with corrupted characters in Excel?
Older versions of Microsoft Excel default to the local Windows code page (like Windows-1252) rather than UTF-8 when opening CSV files directly. Adding a UTF-8 BOM (Byte Order Mark) at the start of the file forces Excel to decode UTF-8 correctly.
Seotud CSV teisenduspaarid
Export Microsoft Excel spreadsheets into clean, comma-separated plain text tables.
Import CSV tabular data into formatted Microsoft Excel XLSX workbooks.
Import tabular CSV spreadsheet records directly into indexed SQLite database tables.
Extract table records and rows from SQL INSERT statements into standardized comma-separated CSV spreadsheets.
Extract multidimensional scientific datasets and numerical matrices from HDF5 (.h5) into tabular CSV format.
Flatten multidimensional NetCDF (.nc) climate and oceanographic variables into comma-separated CSV spreadsheets.
Convert electronic business cards (vCard / VCF) into tabular CSV contact lists for Excel and Google Contacts.