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[csv] shorten and move quote rules to first example

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--- ---
language: CSV name: CSV
contributors: contributors:
- [Timon Erhart, 'https://github.com/turbotimon/'] - [Timon Erhart, 'https://github.com/turbotimon/']
--- ---
CSV (Comma-Separated Values) is a lightweight file format used to store tabular CSV (Comma-Separated Values) is a file format used to store tabular
data in plain text, designed for easy data exchange between programs, data in plain text.
particularly spreadsheets and databases. Its simplicity and human readability
have made it a cornerstone of data interoperability. It is often used for
moving data between programs with incompatible or proprietary formats.
While RFC 4180 provides a standard for the format, in practice, the term "CSV"
is often used more broadly to refer to any text file that:
- Can be interpreted as tabular data
- Uses a delimiter to separate fields (columns)
- Uses line breaks to separate records (rows)
- Optionally includes a header in the first row
```csv ```csv
Name, Age, DateOfBirth Name,Age,DateOfBirth,Comment
Alice, 30, 1993-05-14 Alice,30,1993-05-14,
Bob, 25, 1998-11-02 Bob,25,1998-11-02,
Charlie, 35, 1988-03-21 Eve,,,data might be missing because it's just text
"Charlie Brown",35,1988-03-21,strings can be quoted
"Louis XIV, King of France",76,1638-09-05,strings containing commas must be quoted
"Walter ""The Danger"" White",52,1958-09-07,quotes are escaped by doubling them up
Joe Smith,33,1990-06-02,"multi line strings
span multiple lines
there are no escape characters"
``` ```
## Delimiters for Rows and Columns The first row might be a header of field names or there might be no header and
the first line is already data.
Rows are typically separated by line breaks (`\n` or `\r\n`), while columns ## Delimiters
(fields) are separated by a specific delimiter. Although commas are the most
common delimiter for fields, other characters, such as semicolons (`;`), are
commonly used in regions where commas are decimal separators (e.g., Germany).
Tabs (`\t`) are also used as delimiters in some cases, with such files often
referred to as "TSV" (Tab-Separated Values).
Example using semicolons as delimiter and comma for decimal separator: Rows are separated by line breaks (`\n` or `\r\n`), columns are separated by a comma.
Tabs (`\t`) are sometimes used instead of commas and those files are called "TSVs"
(Tab-Separated Values). They are easier to paste into Excel.
Occasionally other characters can be used, for example semicolons (`;`) may be used
in Europe because commas are [decimal separators](https://en.wikipedia.org/wiki/Decimal_separator)
instead of the decimal point.
```csv ```csv
Name; Age; Grade Name;Age;Grade
Alice; 30; 50,50 Alice;30;50,50
Bob; 25; 45,75 Bob;25;45,75
Charlie; 35; 60,00 Charlie;35;60,00
``` ```
## Data Types ## Data Types
CSV files do not inherently define data types. Numbers and dates are stored as CSV files do not inherently define data types. Numbers and dates are stored as
plain text, and their interpretation depends on the software importing the text. Interpreting and parsing them is left up to software using them.
file. Typically, data is interpreted as follows: Typically, data is interpreted as follows:
```csv ```csv
Data, Comment Data,Comment
100, Interpreted as a number (integer) 100,Interpreted as a number (integer)
100.00, Interpreted as a number (floating-point) 100.00,Interpreted as a number (floating-point)
2024-12-03, Interpreted as a date or a string (depending on the parser) 2024-12-03,Interpreted as a date or a string (depending on the parser)
Hello World, Interpreted as text (string) Hello World,Interpreted as text (string)
"1234", Interpreted as text instead of a number "1234",Interpreted as text instead of a number
``` ```
## Quoting Strings and Special Characters ## Further reading
Quoting strings is only required if the string contains the delimiter, special * [Wikipedia](https://en.wikipedia.org/wiki/Comma-separated_values)
characters, or otherwise could be interpreted as a number. However, it is * [RFC 4180](https://datatracker.ietf.org/doc/html/rfc4180)
often considered good practice to quote all strings to enhance readability and
robustness.
```csv
Quoting strings examples,
Unquoted string,
"Optionally quoted string (good practice)",
"If it contains the delimiter, it needs to be quoted",
"Also, if it contains special characters like \n newlines or \t tabs",
"The quoting "" character itself typically is escaped by doubling the quote ("")",
"or in some systems with a backslash \" (like other escapes)",
```
However, make sure that for one document, the quoting method is consistent.
For example, the last two examples of quoting with either "" or \" would
not be consistent and could cause problems.
## Encoding
Different encodings are used. Most modern CSV files use UTF-8 encoding, but
older systems might use others like ASCII or ISO-8859.
If the file is transferred or shared between different systems, it is a good
practice to explicitly define the encoding used, to avoid issues with
character misinterpretation.
## More Resources
+ [Wikipedia](https://en.wikipedia.org/wiki/Comma-separated_values)
+ [RFC 4180](https://datatracker.ietf.org/doc/html/rfc4180)