The comma-separated values (or CSV; also known as a comma-separated list or comma-separated variables) file format is a file type that stores tabular data. An Internet media type, originally called a MIME type after MIME and sometimes a Content-type after the name of a header in several protocols whose value A file format is a particular way to encode information for storage in a Computer file. The format dates back to the early days of business computing. For this reason, CSV files are common on all computer platforms.

CSV is one implementation of a delimited text file, which uses a comma to separate values (where many implementations of CSV import/export tools allow an alternate separator to be used; as is shown in the MS Access screen shot, below). Formats that use delimiter-separated values (also DSV) store two-dimensional arrays of data by separating the values in each row with specific Delimiter characters A comma ( ,   is a Punctuation mark It has the same shape as an Apostrophe or single closing Quotation mark in many typefaces but it differs However CSV differs from other delimiter separated file formats in using a " (double quote) character around fields that contain reserved characters (such as commas or newlines). Quotation marks or inverted commas (informally referred to as quotes and speech marks) are Punctuation marks used in pairs to set off speech In Computing, a newline (also known as a line break or end-of-line / EOL character is a special character or sequence of characters Most other delimiter formats either use an escape character such as a backslash, or have no support for reserved characters. In Computing and Telecommunication, an escape character is a single character which in a sequence of characters signifies that what is to follow takes an alternative The backslash ( \) is a typographical mark ( Glyph) used chiefly in Computing.

In computer science terms, this type of format is called a "flat file" because only one table can be stored in a CSV file. Computer science (or computing science) is the study and the Science of the theoretical foundations of Information and Computation and their Most systems use a series of tables to store their information, which must be "flattened" into a single table, often with information repeated over several rows, to create a delimited text file. Formats that use delimiter-separated values (also DSV) store two-dimensional arrays of data by separating the values in each row with specific Delimiter characters

A wizard importing a CSV file into MS Access 2007

Specification

While no formal specification for CSV exists, RFC 4180 from October 2005 describes a common format and establishes "text/csv" as the MIME type registered with the IANA. A wizard is a User interface element where the user is presented with a sequence of dialog boxes. An Internet media type, originally called a MIME type after MIME and sometimes a Content-type after the name of a header in several protocols whose value The Internet Assigned Numbers Authority (IANA is the entity that oversees global IP address allocation, DNS root zone management, media types Another relevant specification is provided by Fielded Text which also covers the CSV format. Fielded Text is a proposed standard which provides structure and schema definition to text files which contain tables of values (for example CSV files

Since csv files existed well before 2005 the RFC is only one special view on csv files.

Many informal documents exist that describe the CSV format. How To: The Comma Separated Value (CSV) File Format provides an overview of the CSV format in the most widely used applications and explains how it can best be used and supported.

The basic rules from a lot of these specifications are as follows:

CSV is a delimited data format that has fields/columns separated by the comma character and records/rows separated by newlines. Formats that use delimiter-separated values (also DSV) store two-dimensional arrays of data by separating the values in each row with specific Delimiter characters In Computer science, data that has several parts can be divided into fields. A comma ( ,   is a Punctuation mark It has the same shape as an Apostrophe or single closing Quotation mark in many typefaces but it differs In Typography, a grapheme is the fundamental unit in written language. In the context of a Relational database, a row —also called a record or tuple —represents a single implicitly structured Data item in a In Computing, a newline (also known as a line break or end-of-line / EOL character is a special character or sequence of characters Fields that contain a special character (comma, newline, or double quote), must be enclosed in double quotes. Quotation marks or inverted commas (informally referred to as quotes and speech marks) are Punctuation marks used in pairs to set off speech However, if a line contains a single entry which is the empty string, it may be enclosed in double quotes. If a field's value contains a double quote character it is escaped by placing another double quote character next to it. In Computing and Telecommunication, an escape character is a single character which in a sequence of characters signifies that what is to follow takes an alternative The CSV file format does not require a specific character encoding, byte order, or line terminator format. A character encoding consists of a code that pairs a sequence of characters from a given character set (sometimes incorrectly referred to as Code page

• Each record is one line terminated by a line feed (ASCII/LF=0x0A) or a carriage return and line feed pair (ASCII/CRLF=0x0D 0x0A), however, line-breaks can be embedded.
• Fields are separated by commas.

1997,Ford,E350

• In some CSV implementations, leading and trailing spaces or tabs, adjacent to commas, are trimmed. This practice is contentious and in fact is specifically prohibited by RFC 4180, which states, "Spaces are considered part of a field and should not be ignored. "

1997,   Ford   , E350same as1997,Ford,E350

• Fields with embedded commas must be delimited with double-quote characters.

1997,Ford,E350,"Super, luxurious truck"

• Fields with embedded double-quote characters must be delimited with double-quote characters, and the embedded double-quote characters must be represented by a pair of double-quote characters.

1997,Ford,E350,"Super ""luxurious"" truck"

• Fields with embedded line breaks must be delimited by double-quote characters.

1997,Ford,E350,"Go get one nowthey are going fast"

• Fields with leading or trailing spaces must be delimited by double-quote characters. (See comment about leading and trailing spaces above. )

1997,Ford,E350,"  Super luxurious truck    "

• Fields may always be delimited by double-quote characters, whether necessary or not.

"1997","Ford","E350"

• The first record in a csv file may contain column names in each of the fields.

Year,Make,Model1997,Ford,E3502000,Mercury,Cougar

Example

The above table of data may be represented in CSV format as follows:

1997,Ford,E350,"ac, abs, moon",3000. 001999,Chevy,"Venture ""Extended Edition""","",4900. 001996,Jeep,Grand Cherokee,"MUST SELL!
air, moon roof, loaded",4799. 00

This CSV example illustrates that:

• fields that contain commas, double-quotes, or line-breaks must be quoted,
• a quote within a field must be escaped with an additional quote immediately preceding the literal quote,
• space before and after delimiter commas may be trimmed, and
• a line break within an element must be preserved.

Application support

Main article: CSV application support

The CSV file format is very simple and supported by almost all spreadsheets and database management systems. The Comma-separated values file format is a very simple data file format that is supported by almost all Spreadsheet software such as Excel (although Excel uses the A spreadsheet is a Computer application that simulates a paper worksheet A database management system ( DBMS) is Computer software designed for the purpose of managing Databases DBMSes may use any of a variety of Data models Many programming languages have libraries available that support CSV files. A programming language is an Artificial language that can be used to write programs which control the behavior of a machine particularly a Computer. Even modern software applications support CSV imports and/or exports because the format is so widely recognized. In fact, many applications allow . csv-named files to use any delimiter character.

See also

• Delimiter-separated values
• Fielded text

External links

• RFC 4180: Common Format and MIME Type for Comma-Separated Values (CSV) Files
• How To: The Comma Separated Value (CSV) File Format
• An EBNF definition of the CSV format with explanation