Changes

This [[Module Library|XQuery Module]] contains a single function to parse CSV input. [httphttps://en.wikipedia.org/wiki/Comma-separated_values CSV] (comma-separated values) is a popular representation for tabular data, exported e. g. from Excel.

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><nowiki>http://basex.org/errors</nowiki></code> namespace, which is statically bound to the {{Code|bxerr}} prefix.

==ConversionFormats==

If the {{Code|direct}} or {{Code|attributes}} format is chosen, a CSV string is converted to XML as follows:

* The resulting XML document has a {{Code|<csv>}} root element.* Rows are represented via {{Code|<record>}} elements.* 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:** Empty names are represented by a single underscore ({{Code|_}}), and characters that are not valid in element names are replaced with underscores or (when invalid as first character of an element name) prefixed with an underscore.** If the {{Code|laxformat}} option is set to {{Code|falsedirect}}, invalid characters will be rewritten to an underscore and the character’s four-digit Unicodefield names are encoded, as described in the [[Conversion Module#Keys|Conversion Module]], and underscores will be represented used as two underscores ({{Code|__}}). The resulting element names may be less readable, but can always be converted back to the original field names.* If * Otherwise, if {{Code|format}} is set to {{Code|attributes}}, the field names will be stored in name attributes.

If {{Code|format}} is set to {{Code|map}}, the CSV data will be converted to an ===XQuery map:===

* All records are enumerated with positive integers.* By default, all entries of a records are represented in a sequence.* If With the {{Code|headerxquery}} option is set format, CSV records are converted to {{Code|true}}, a map is created, which contains all field names and its values.sequence of arrays:

'''A little advice''': in * The resulting value will be a map with a {{Code|records}} entry and an optional {{Code|names}} entry.* Records are organized as a sequence of arrays. An array contains the Database Creation dialog entries of a single record.* The {{Code|names}} entry contains an array with the GUI, column names. It is generated if you select the {{Code|header}} option is set to {{Code|true}}. The CSV Parsing and switch to 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:<pre lang='xquery'Parsing>for $record at $pos in $csv?recordsreturn $pos || ". " || string-join($record?*, ', ' tab)</pre> The resulting representation consumes less memory than XML-based formats, you and values can see the effects of some of the be directly accessed without conversion options. Thus, it is recommendable for very large inputs and for efficient ad-hoc processing.

{{Mark|Updated with Version 8.6}}: improved Excel compatibility In the following table, all available options are listed. The Excel column indicates what are the preferred lists recommended options for data that is to be imported, processed with Excel or has been exported from ExcelOpen/Libre Office.

! width="140" | Option! width="50%" | Description

| Defines the character which separates the entries values of a single record in a single line.

| ''parse'', ''serialize''| {{Code|semicolon}}or {{Code|comma}}, depending on the region

| Specifies the format of the XML for converting CSV data([[#Conversion Formats|see above]]). The format is only relevant if the {{Code|header}} option is activated:<br/>* 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|map}} conversion, the input is converted to an XQuery map| {{Code|direct}}, {{Code|attributes}}, {{Code|mapxquery}}

| Specifies if a [[Conversion Module#Keys|lax approach is conversion rules]] are used to convert QNames to JSON names.

* Serialization: If the option is enabled, the value will be wrapped with quotesif 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.

|-valign="top"| width='120' | '''SignaturesSignature'''|{{Func|csv:parse|$input as xs:string|document-node(element(csv))}}<br/pre>{{Func|csv:parse|( $input value as xs:string?, $options as map(xs*)? :string, item(= map { }))|as item()}}?</pre>|-valign="top"

|Converts the CSV data specified by {{Code|$inputvalue}} to an XML document or a mapXQuery value. The {{Code|$options}} argument can be used to control the way the input is converted.|-valign="top"

|{{Error|BXCS0001parse|#Errors}} the specified input cannot be parsedas CSV document.

|-valign="top"| width='120' | '''SignaturesSignature'''|{{Func|csv:serialize|$input as node()|xs:string}}<br/pre>{{Func|csv:serialize|( $input as nodeitem()?, $options as map(xs*)? :string, item(= map { }))|as xs:string}}</pre>|-valign="top"

|Serializes the node specified by {{Code|$input}} as CSV data, and returns using the result as specified {{Code|xs:string$options}}, and returns the result as string. Items Values can also be serialized as JSON if CSV with the standard [[Serialization|Serialization Parameter]] feature of XQuery:* The parameter {{Code|method}} is needs to be set to {{Code|csv}}.<br/>The , and* the options presented in this article need to be assigned to the {{Code|$optionscsv}} argument can be used to control the way the input is serializedparameter.|-valign="top"

|{{Error|BXCS0002serialize|#Errors}} the input cannot be serialized.

<pre classlang="brush:xml">

<pre classlang="brush:'xquery"'>

<pre classlang="brush:xml">

<pre classlang="brush:'xquery"'>let $text := file:read-text('some-data.csv')

let $xml input := csvfile:parseread-text($text, $options'some-data.csv')let $output := $input => csv :parse($options) = > csv:serialize($xml, $options)return $text input eq $csvoutput

'''Example 3:''' Converts CSV data to an XQuery map item and serializes its contentsreturns distinct column values:

<pre classlang="brush:'xquery"'>let $text := "``[Name;,City" || out:nl() || "Jack,ChicagoJack,WashingtonJohn;Newton" || out:nl() || "Jack;Oldtown",New York]``let $options := map { 'separatorformat': ';xquery','header': true() }let $csv := csv:parse($text, $options)return ( 'formatDistinct values:' , let $records : = $csv('maprecords',) for $name at $pos in $csv('headernames' )?* let $values : true= $records?($pos)} return (return csv '* ' || $name || ':parse' || string-join(distinct-values($textvalues), ', $options') ))

<pre classlang="brush:xml"'xquery'>{ 1Distinct values: { "City"* Name: "Newton"Jack, "Name": "John" }, 2: { "* City": "Oldtown"Chicago, "Name": "Jack" }}Washington, New York

|-valign="top"|{{Code|BXCS0001parse}}

|-valign="top"|{{Code|BXCS0002serialize}}

* Updated: [[#csv:parse{{Function||csv:parse]] }} now returns a document node instead of an element, or an XQuery map if {{Code|format}} is set to {{Code|map}}.