Difference between revisions of "CSV Module"

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This [[Module Library|XQuery Module]] contains a single function to parse CSV input. [http://en.wikipedia.org/wiki/Comma-separated_values CSV] (comma-separated values) is a popular representation for tabular data, exported e. g. from Excel.
+
This [[Module Library|XQuery Module]] contains a single function to parse CSV input. [https://en.wikipedia.org/wiki/Comma-separated_values CSV] (comma-separated values) is a popular representation for tabular data, exported e. g. from Excel.
  
 
=Conventions=
 
=Conventions=
  
All functions in this module are assigned to the {{Code|http://basex.org/modules/csv}} namespace, which is statically bound to the {{Code|csv}} prefix.<br/>
+
All functions and errors in this module are assigned to the <code><nowiki>http://basex.org/modules/csv</nowiki></code> namespace, which is statically bound to the {{Code|csv}} prefix.<br/>
All errors are assigned to the {{Code|http://basex.org/errors}} namespace, which is statically bound to the {{Code|bxerr}} prefix.
 
  
 
==Conversion==
 
==Conversion==
Line 10: Line 9:
 
===XML: Direct, Attributes===
 
===XML: Direct, Attributes===
  
CSV is converted to XML as follows:
+
If the {{Code|direct}} or {{Code|attributes}} format is chosen, a CSV string is converted to XML:
  
* The resulting XML document has a {{Code|<csv>}} root element.
+
* The resulting XML document has a {{Code|csv}} root element.
* Rows are represented via {{Code|<record>}} elements.
+
* Rows are represented via {{Code|record}} elements.
* Fields are represented via {{Code|<entry>}} elements. The value of a field is represented as text node.
+
* Fields are represented via {{Code|entry}} elements. The value of a field is represented as text node.
* If the {{Code|header}} option is set to {{Code|true}}, the first text line is parsed as table header, and the {{Code|<entry>}} elements are replaced with the field names:
+
* If the {{Code|header}} option is set to {{Code|true}}, the first text line is parsed as table header:
** Empty names are represented by a single underscore ({{Code|_}}), and characters that are not valid in element names are replaced with underscores.
+
** If {{Code|format}} is set to {{Code|direct}}, the field names are encoded, as described in the [[Conversion Module#Keys|Conversion Module]], and used as element names.
** If the {{Code|lax}} option is set to {{Code|false}}, invalid characters will be rewritten to an underscore and the character’s four-digit Unicode, and underscores will be represented as two underscores ({{Code|__}}). The resulting element names may be less readable, but can always be converted back to the original field names.
+
** Otherwise, if {{Code|format}} is {{Code|attributes}}, the field names will be stored in name attributes.
* If {{Code|format}} is set to {{Code|attributes}}, field names will be stored in name attributes.
 
  
In the Database Creation dialog of the GUI, when the CSV parser is selected, the ''Parsing'' tab demonstrates the conversion of CSV to XML and the effects of the single conversion options.
+
'''A little advice''': in the Database Creation dialog of the GUI, if you select CSV Parsing and switch to the ''Parsing'' tab, you can see the effects of some of the conversion options.
  
===Map===
+
===XQuery===
  
If {{Code|format}} is set to {{Code|map}}, the CSV data will be converted to an XQuery map:
+
With the {{Code|xquery}} format, CSV records are converted to a sequence of arrays:
  
* All records are enumerated with positive integers.
+
* The resulting value will be a map with a {{Code|records}} and an optional {{Code|names}} key.
* By default, all entries of a records are represented in a sequence.
+
* Records are organized as a sequence of arrays. A single array contains the entries of a single record.
* If the {{Code|header}} option is set to {{Code|true}}, a map is created, which contains all field names and its values.
+
* The column names will be available if {{Code|header}} option is set to {{Code|true}}.
 +
 
 +
The CSV map can e.g. be accessed as follows:
 +
 
 +
* <code>$csv?records[5]</code> returns all entries of the 5th record (row)
 +
* <code>$csv?records?(2)</code> returns all entries of the 2nd field (column)
 +
* <code>$csv?names?*</code> returns the names of all fields (if available)
 +
* Return enumerated strings for all records:
 +
<syntaxhighlight lang="xquery">
 +
for $record at $pos in $csv?records
 +
return $pos || ". " || string-join($record?*, ', ')
 +
</syntaxhighlight>
 +
 
 +
The resulting representation consumes less memory than XML-based formats, and values can be directly accessed without conversion. Thus, it is recommendable for very large inputs and for efficient ad-hoc processing.
  
 
==Options==
 
==Options==
  
The following options are available:
+
In the following table, all available options are listed. The Excel column lists recommended options for data that is processed with Excel or Open/Libre Office.
  
 
{| class="wikitable sortable" width="100%"
 
{| class="wikitable sortable" width="100%"
 
|- valign="top"
 
|- valign="top"
! width="140" | Option
+
! Option
! width="50%" | Description
+
! Description
 
! Allowed
 
! Allowed
 
! Default
 
! Default
 +
! Direction
 +
! Excel
 
|- valign="top"
 
|- valign="top"
 
| {{Code|separator}}
 
| {{Code|separator}}
| Defines the character which separates the entries of a record in a single line.
+
| Defines the character which separates the values of a single record.
 
| {{Code|comma}}, {{Code|semicolon}}, {{Code|colon}}, {{Code|tab}}, {{Code|space}} or a ''single character''
 
| {{Code|comma}}, {{Code|semicolon}}, {{Code|colon}}, {{Code|tab}}, {{Code|space}} or a ''single character''
 
| {{Code|comma}}
 
| {{Code|comma}}
 +
| ''parse'', ''serialize''
 +
| {{Code|semicolon}} or {{Code|comma}}, depending on the region
 
|- valign="top"
 
|- valign="top"
 
| {{Code|header}}
 
| {{Code|header}}
Line 50: Line 65:
 
| {{Code|yes}}, {{Code|no}}
 
| {{Code|yes}}, {{Code|no}}
 
| {{Code|no}}
 
| {{Code|no}}
 +
| ''parse'', ''serialize''
 +
|
 
|- valign="top"
 
|- valign="top"
 
| {{Code|format}}
 
| {{Code|format}}
| Specifies the format of the XML data. The format is only relevant if the {{Code|header}} option is activated:<br/>
+
| Specifies the format of the XML data:<br/>
 
* With {{Code|direct}} conversion, field names are represented as element names
 
* With {{Code|direct}} conversion, field names are represented as element names
 
* With {{Code|attributes}} conversion, field names are stored in {{Code|name}} attributes
 
* With {{Code|attributes}} conversion, field names are stored in {{Code|name}} attributes
* With {{Code|map}} conversion, the input is converted to an XQuery map
+
* With {{Code|xquery}} conversion, the input is converted to an XQuery map
| {{Code|direct}}, {{Code|attributes}}, {{Code|map}}
+
| {{Code|direct}}, {{Code|attributes}}, {{Code|xquery}}
 
| {{Code|direct}}
 
| {{Code|direct}}
 +
| ''parse'', ''serialize''
 +
|
 
|- valign="top"
 
|- valign="top"
 
| {{Code|lax}}
 
| {{Code|lax}}
Line 63: Line 82:
 
| {{Code|yes}}, {{Code|no}}
 
| {{Code|yes}}, {{Code|no}}
 
| {{Code|yes}}
 
| {{Code|yes}}
 +
| ''parse'', ''serialize''
 +
| {{Code|no}}
 +
|- valign="top"
 +
| {{Code|quotes}}
 +
| Specifies how quotes are parsed:
 +
* Parsing: If the option is enabled, quotes at the start and end of a value will be treated as control characters. Separators and newlines within the quotes will be adopted without change.
 +
* Serialization: If the option is enabled, the value will be wrapped with quotes if it contains characters that might be treated as control characters. A quote character in the value will be encoded according to the rules of the {{Code|backslashes}} option.
 +
| {{Code|yes}}, {{Code|no}}
 +
| {{Code|yes}}
 +
| ''parse'', ''serialize''
 +
| {{Code|yes}}
 +
|- valign="top"
 +
| {{Code|backslashes}}
 +
| Specifies how quotes and other characters are escaped:
 +
* Parsing: If the option is enabled, {{Code|\r}}, {{Code|n}} and {{Code|\t}} will be replaced with the corresponding control characters. All other escaped characters will be adopted as literals (e.g.: {{Code|\"}} → {{Code|"}}). If the option is disabled, two consecutive quotes will be replaced with a single quote (unless {{Code|quotes}} is enabled and the quote is the first or last character of a value).
 +
* Serialization: If the option is enabled, {{Code|\r}}, {{Code|n}}, {{Code|\t}}, {{Code|"}} and the separator character will be encoded with a backslash. If the option is disabled, quotes will be duplicated.
 +
| {{Code|yes}}, {{Code|no}}
 +
| {{Code|no}}
 +
| ''parse'', ''serialize''
 +
| {{Code|no}}
 +
|- valign="top"
 +
| {{Code|allow}}
 +
| In Excel, a value will be evaluated if it starts with the character {{Code|-}}, {{Code|+}}, <code>=</code>, {{Code|@}}, {{Code|\t}} or {{Code|\r}}. A regular expression can be specified to reject data that will be handled differently than expected by an application, or that may be malicious (see https://owasp.org/www-community/attacks/CSV_Injection for more details).
 +
| ''string''
 +
|
 +
| ''serialize''
 +
| <code><nowiki>[^-+=\t\r].*|[-+]\d*([,.]\d+)?</nowiki></code>
 
|}
 
|}
  
The CSV function signatures provide an {{Code|$options}} argument. Options can either be specified
+
=Functions=
* as children of an {{Code|<csv:options/>}} element; e.g.:
+
 
<pre class="brush:xml">
+
==csv:doc==
<csv:options>
 
  <csv:separator value=';'/>
 
  ...
 
</csv:options>
 
</pre>
 
* or as map, which contains all key/value pairs:
 
<pre class="brush:xquery">
 
{ 'separator': ';', ... }
 
</pre>
 
  
=Functions=
+
{| width='100%'
 +
|- valign="top"
 +
| width='120' | '''Signatures'''
 +
|{{Func|csv:doc|$uri as xs:string?|item()?}}<br />{{Func|csv:doc|$uri as xs:string?, $options as map(*)?|item()?}}<br />
 +
|- valign="top"
 +
| '''Summary'''
 +
|Fetches the CSV document referred to by the given {{Code|$uri}} and converts it to an XQuery value. The {{Code|$options}} argument can be used to control the way the input is converted.
 +
|- valign="top"
 +
| '''Errors'''
 +
|{{Error|parse|#Errors}} the specified input cannot be parsed as CSV document.<br/>{{Error|options|#Errors}} the specified options are conflicting.
 +
|}
  
 
==csv:parse==
 
==csv:parse==
 
{{Version|7.8}}: [[#csv:parse|csv:parse]] now returns a document node instead of an element, or an XQuery map if {{Code|format}} is set to {{Code|map}}. New options have been added.
 
  
 
{| width='100%'
 
{| width='100%'
|-
+
|- valign="top"
 
| width='120' | '''Signatures'''
 
| width='120' | '''Signatures'''
|{{Func|csv:parse|$input as xs:string|document-node(element(csv))}}<br/>{{Func|csv:parse|$input as xs:string, $options as item()|item()}}
+
|{{Func|csv:parse|$string as xs:string?|item()?}}<br/>{{Func|csv:parse|$string as xs:string?, $options as map(*)?|item()?}}
|-
+
|- valign="top"
 
| '''Summary'''
 
| '''Summary'''
|Converts the CSV data specified by {{Code|$input}} to an XML document or a map. The {{Code|$options}} argument can be used to control the way the input is converted.
+
|Converts the CSV {{Code|$string}} to an XQuery value. The {{Code|$options}} argument can be used to control the way the input is converted.
|-
+
|- valign="top"
 
| '''Errors'''
 
| '''Errors'''
|{{Error|BXCS0001|#Errors}} the input cannot be parsed.
+
|{{Error|parse|#Errors}} the specified input cannot be parsed as CSV document.
 
|}
 
|}
  
 
==csv:serialize==
 
==csv:serialize==
 +
 
{| width='100%'
 
{| width='100%'
|-
+
|- valign="top"
 
| width='120' | '''Signatures'''
 
| width='120' | '''Signatures'''
|{{Func|csv:serialize|$input as node(), $options as item()|xs:string}}
+
|{{Func|csv:serialize|$input as item()?|xs:string}}<br/>{{Func|csv:serialize|$input as item()?, $options as map(*)?|xs:string}}
|-
+
|- valign="top"
 
| '''Summary'''
 
| '''Summary'''
|Serializes the node specified by {{Code|$input}} as CSV data, and returns the result as {{Code|xs:string}}.Items can also be serialized as JSON if the [[Serialization|Serialization Parameter]] {{Code|method}} is set to {{Code|csv}}.<br/>The {{Code|$options}} argument can be used to control the way the input is serialized.
+
|Serializes the specified {{Code|$input}} as CSV, using the specified {{Code|$options}}, and returns the result as string.
|-
+
Values can also be serialized as CSV with the standard [[Serialization]] feature of XQuery:
 +
* The parameter {{Code|method}} needs to be set to {{Code|csv}}, and
 +
* the options presented in this article need to be assigned to the {{Code|csv}} parameter.
 +
|- valign="top"
 
| '''Errors'''
 
| '''Errors'''
|{{Error|BXCS0002|#Errors}} the input cannot be serialized.
+
|{{Error|serialize|#Errors}} the input cannot be serialized.
 
|}
 
|}
  
Line 114: Line 163:
  
 
'''Input''' {{Code|addressbook.csv}}:
 
'''Input''' {{Code|addressbook.csv}}:
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
 
Name,First Name,Address,City
 
Name,First Name,Address,City
 
Huber,Sepp,Hauptstraße 13,93547 Hintertupfing
 
Huber,Sepp,Hauptstraße 13,93547 Hintertupfing
</pre>
+
</syntaxhighlight>
  
 
'''Query:'''
 
'''Query:'''
<pre class="brush:xquery">
+
<syntaxhighlight lang="xquery">
 
let $text := file:read-text('addressbook.csv')
 
let $text := file:read-text('addressbook.csv')
return csv:parse($text, { 'header': true() })
+
return csv:parse($text, map { 'header': true() })
</pre>
+
</syntaxhighlight>
  
 
'''Result:'''
 
'''Result:'''
<pre class="brush:xml">
+
<syntaxhighlight lang="xml">
 
<csv>
 
<csv>
 
   <record>
 
   <record>
Line 135: Line 184:
 
   </record>
 
   </record>
 
</csv>
 
</csv>
</pre>
+
</syntaxhighlight>
 
'''
 
'''
  
Line 141: Line 190:
  
 
'''Query:'''
 
'''Query:'''
<pre class="brush:xquery">
+
<syntaxhighlight lang="xquery">
let $text := file:read-text('some-data.csv')
+
let $options := map { 'lax': false() }
let $options := { 'lax': 'no' }
+
let $input := file:read-text('some-data.csv')
let $xml := csv:parse($text, $options)
+
let $output := $input => csv:parse($options) => csv:serialize($options)
let $csv := csv:serialize($xml, $options)
+
return $input eq $output
return $text eq $csv
+
</syntaxhighlight>
</pre>
 
  
'''Example 3:''' Converts CSV data to an XQuery map item and serializes its contents:
+
'''Example 3:''' Converts CSV data to XQuery and returns distinct column values:
  
 
'''Query:'''
 
'''Query:'''
<pre class="brush:xquery">
+
<syntaxhighlight lang="xquery">
let $text := "Name;City" || out:nl() || "John;Newton" || out:nl() || "Jack;Oldtown"
+
let $text := ``[Name,City
let $options :=
+
Jack,Chicago
  <csv:options>
+
Jack,Washington
    <csv:separator value=';'/>
+
John,New York
    <csv:format value='map'/>
+
]``
    <csv:header value='yes'/>
+
let $options := map { 'format': 'xquery', 'header': true() }
   </csv:options>
+
let $csv := csv:parse($text, $options)
let $map := csv:parse($text, $options)
+
return (
return map:serialize($map)
+
  'Distinct values:',
</pre>
+
  let $records := $csv('records')
 +
  for $name at $pos in $csv('names')?*
 +
   let $values := $records?($pos)
 +
  return (
 +
    '* ' || $name || ': ' || string-join(distinct-values($values), ', ')
 +
  )
 +
)
 +
</syntaxhighlight>
  
 
'''Result:'''
 
'''Result:'''
<pre class="brush:xml">
+
<syntaxhighlight lang="xquery">
{
+
Distinct values:
  1: {
+
* Name: Jack, John
    "City": "Newton",
+
* City: Chicago, Washington, New York
    "Name": "John"
+
</syntaxhighlight>
  },
 
  2: {
 
    "City": "Oldtown",
 
    "Name": "Jack"
 
  }
 
}
 
</pre>
 
  
 
=Errors=
 
=Errors=
Line 183: Line 231:
 
! width="110"|Code
 
! width="110"|Code
 
|Description
 
|Description
|-
+
|- valign="top"
|{{Code|BXCS0001}}
+
|{{Code|parse}}
 
| The input cannot be parsed.
 
| The input cannot be parsed.
|-
+
|- valign="top"
|{{Code|BXCS0002}}
+
|{{Code|serialize}}
 
| The node cannot be serialized.
 
| The node cannot be serialized.
 
|}
 
|}
  
 
=Changelog=
 
=Changelog=
 +
 +
;Version 9.7
 +
* Added: [[#Options|Options]]: <code>allow</code> option.
 +
 +
;Version 9.4
 +
* Added: {{Function||csv:doc}}
 +
 +
; Version 9.1
 +
* Updated: {{Function||csv:parse}} can be called with empty sequence.
 +
 +
;Version 9.0
 +
 +
* Added: {{Code|xquery}} option
 +
* Removed: {{Code|map}} option
 +
* Updated: error codes updated; errors now use the module namespace
 +
 +
;Version 8.6
 +
 +
* Updated: [[#Options|Options]]: improved Excel compatibility
 +
 +
;Version 8.0
 +
 +
* Added: {{Code|backslashes}} option
  
 
;Version 7.8
 
;Version 7.8
  
* Updated: [[#csv:parse|csv:parse]] now returns a document node instead of an element, or an XQuery map if {{Code|format}} is set to {{Code|map}}.
+
* Updated: {{Function||csv:parse}} now returns a document node instead of an element, or an XQuery map if {{Code|format}} is set to {{Code|map}}.
 
* Added: {{Code|format}} and {{Code|lax}} options
 
* Added: {{Code|format}} and {{Code|lax}} options
  
 
The module was introduced with Version 7.7.2.
 
The module was introduced with Version 7.7.2.
 
[[Category:XQuery]]
 

Revision as of 13:17, 20 July 2022

This XQuery Module contains a single function to parse CSV input. CSV (comma-separated values) is a popular representation for tabular data, exported e. g. from Excel.

Conventions

All functions and errors in this module are assigned to the http://basex.org/modules/csv namespace, which is statically bound to the csv prefix.

Conversion

XML: Direct, Attributes

If the direct or attributes format is chosen, a CSV string is converted to XML:

  • The resulting XML document has a csv root element.
  • Rows are represented via record elements.
  • Fields are represented via entry elements. The value of a field is represented as text node.
  • If the header option is set to true, the first text line is parsed as table header:
    • If format is set to direct, the field names are encoded, as described in the Conversion Module, and used as element names.
    • Otherwise, if format is attributes, the field names will be stored in name attributes.

A little advice: in the Database Creation dialog of the GUI, if you select CSV Parsing and switch to the Parsing tab, you can see the effects of some of the conversion options.

XQuery

With the xquery format, CSV records are converted to a sequence of arrays:

  • The resulting value will be a map with a records and an optional names key.
  • Records are organized as a sequence of arrays. A single array contains the entries of a single record.
  • The column names will be available if header option is set to true.

The CSV map can e.g. be accessed as follows:

  • $csv?records[5] returns all entries of the 5th record (row)
  • $csv?records?(2) returns all entries of the 2nd field (column)
  • $csv?names?* returns the names of all fields (if available)
  • Return enumerated strings for all records:

<syntaxhighlight lang="xquery"> for $record at $pos in $csv?records return $pos || ". " || string-join($record?*, ', ') </syntaxhighlight>

The resulting representation consumes less memory than XML-based formats, and values can be directly accessed without conversion. Thus, it is recommendable for very large inputs and for efficient ad-hoc processing.

Options

In the following table, all available options are listed. The Excel column lists recommended options for data that is processed with Excel or Open/Libre Office.

Option Description Allowed Default Direction Excel
separator Defines the character which separates the values of a single record. comma, semicolon, colon, tab, space or a single character comma parse, serialize semicolon or comma, depending on the region
header Indicates if the first line of the parsed or serialized CSV data is a table header. yes, no no parse, serialize
format Specifies the format of the XML data:
  • With direct conversion, field names are represented as element names
  • With attributes conversion, field names are stored in name attributes
  • With xquery conversion, the input is converted to an XQuery map
direct, attributes, xquery direct parse, serialize
lax Specifies if a lax approach is used to convert QNames to JSON names. yes, no yes parse, serialize no
quotes Specifies how quotes are parsed:
  • Parsing: If the option is enabled, quotes at the start and end of a value will be treated as control characters. Separators and newlines within the quotes will be adopted without change.
  • Serialization: If the option is enabled, the value will be wrapped with quotes if it contains characters that might be treated as control characters. A quote character in the value will be encoded according to the rules of the backslashes option.
yes, no yes parse, serialize yes
backslashes Specifies how quotes and other characters are escaped:
  • Parsing: If the option is enabled, \r, n and \t will be replaced with the corresponding control characters. All other escaped characters will be adopted as literals (e.g.: \""). If the option is disabled, two consecutive quotes will be replaced with a single quote (unless quotes is enabled and the quote is the first or last character of a value).
  • Serialization: If the option is enabled, \r, n, \t, " and the separator character will be encoded with a backslash. If the option is disabled, quotes will be duplicated.
yes, no no parse, serialize no
allow In Excel, a value will be evaluated if it starts with the character -, +, =, @, \t or \r. A regular expression can be specified to reject data that will be handled differently than expected by an application, or that may be malicious (see https://owasp.org/www-community/attacks/CSV_Injection for more details). string serialize [^-+=\t\r].*|[-+]\d*([,.]\d+)?

Functions

csv:doc

Signatures csv:doc($uri as xs:string?) as item()?
csv:doc($uri as xs:string?, $options as map(*)?) as item()?
Summary Fetches the CSV document referred to by the given $uri and converts it to an XQuery value. The $options argument can be used to control the way the input is converted.
Errors parse: the specified input cannot be parsed as CSV document.
options: the specified options are conflicting.

csv:parse

Signatures csv:parse($string as xs:string?) as item()?
csv:parse($string as xs:string?, $options as map(*)?) as item()?
Summary Converts the CSV $string to an XQuery value. The $options argument can be used to control the way the input is converted.
Errors parse: the specified input cannot be parsed as CSV document.

csv:serialize

Signatures csv:serialize($input as item()?) as xs:string
csv:serialize($input as item()?, $options as map(*)?) as xs:string
Summary Serializes the specified $input as CSV, using the specified $options, and returns the result as string.

Values can also be serialized as CSV with the standard Serialization feature of XQuery:

  • The parameter method needs to be set to csv, and
  • the options presented in this article need to be assigned to the csv parameter.
Errors serialize: the input cannot be serialized.

Examples

Example 1: Converts CSV data to XML, interpreting the first row as table header:

Input addressbook.csv: <syntaxhighlight lang="xml"> Name,First Name,Address,City Huber,Sepp,Hauptstraße 13,93547 Hintertupfing </syntaxhighlight>

Query: <syntaxhighlight lang="xquery"> let $text := file:read-text('addressbook.csv') return csv:parse($text, map { 'header': true() }) </syntaxhighlight>

Result: <syntaxhighlight lang="xml"> <csv>

 <record>
   <Name>Huber</Name>
   <First_Name>Sepp</First_Name>
   <Address>Hauptstraße 13</Address>
   <City>93547 Hintertupfing</City>
 </record>

</csv> </syntaxhighlight>

Example 2: Converts some CSV data to XML and back, and checks if the input and output are equal. The expected result is true:

Query: <syntaxhighlight lang="xquery"> let $options := map { 'lax': false() } let $input := file:read-text('some-data.csv') let $output := $input => csv:parse($options) => csv:serialize($options) return $input eq $output </syntaxhighlight>

Example 3: Converts CSV data to XQuery and returns distinct column values:

Query: <syntaxhighlight lang="xquery"> let $text := ``[Name,City Jack,Chicago Jack,Washington John,New York ]`` let $options := map { 'format': 'xquery', 'header': true() } let $csv := csv:parse($text, $options) return (

 'Distinct values:',
 let $records := $csv('records')
 for $name at $pos in $csv('names')?*
 let $values := $records?($pos)
 return (
   '* ' || $name || ': ' || string-join(distinct-values($values), ', ')
 )

) </syntaxhighlight>

Result: <syntaxhighlight lang="xquery"> Distinct values:

  • Name: Jack, John
  • City: Chicago, Washington, New York

</syntaxhighlight>

Errors

Code Description
parse The input cannot be parsed.
serialize The node cannot be serialized.

Changelog

Version 9.7
Version 9.4
Version 9.1
  • Updated: csv:parse can be called with empty sequence.
Version 9.0
  • Added: xquery option
  • Removed: map option
  • Updated: error codes updated; errors now use the module namespace
Version 8.6
  • Updated: Options: improved Excel compatibility
Version 8.0
  • Added: backslashes option
Version 7.8
  • Updated: csv:parse now returns a document node instead of an element, or an XQuery map if format is set to map.
  • Added: format and lax options

The module was introduced with Version 7.7.2.