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.

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:

'''* The resulting value will be a map with a {{Code|records}} and an optional {{Code|names}} key.* Records are organized as a sequence of arrays. A little advice''': in single array contains the Database Creation dialog entries of the GUI, a single record.* The column names will be available if you select {{Code|header}} option is set to {{Code|true}}. The CSV Parsing and switch to the ''Parsing'' tab, you map can see the effects of some of the conversion optionse.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==Options=="xquery">for $record at $pos in $csv?recordsreturn $pos || ". " || string-join($record?*, ', ')</syntaxhighlight>

{{Mark|Updated with Version 8The 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.6}}: improved Excel compatibility

The In the following table, all available options are available:listed. The Excel column indicates what are the preferred options for data that is to be imported, or has been exported from Excel.

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

| Specifies the format of the XML data. The format is only relevant if the {{Code|header}} option is activated:<br/>

* With {{Code|mapxquery}} conversion, the input is converted to an XQuery map| {{Code|direct}}, {{Code|attributes}}, {{Code|mapxquery}}

* Serialization: If the option is enabled, the value will be wrapped with quotesif it contains characters that might be treated as control characters. Quote characters A quote character in the value will be encoded according to the rules of the {{Code|backslashes}} option.

* 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 (see the unless {{Code|quotes}} option for exceptionsis 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 escaped encoded with a backslash. If the option is disabled, quotes will be duplicated.

|{{Func|csv:parse|$input string as xs:string?|document-nodeitem(element(csv))?}}<br/>{{Func|csv:parse|$input string as xs:string?, $options as map(*)?|item()?}}|-| '''Summary'''|Converts the CSV {{Code|$string}} to an XQuery value. The {{Code|$options}} argument can be used to control the way the input is converted.|-| '''Errors'''|{{Error|parse|#Errors}} the specified input cannot be parsed as CSV document.|} ==csv:doc== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|csv:doc|$uri as xs:string, ?|item()?}}<br />{{Func|csv:doc|$uri as xs:string?, $options as map(*)?|item()?}}<br />

|Converts Fetches the CSV data specified document referred to by the given {{Code|$inputuri}} and converts it to an XML document or a mapXQuery value. The {{Code|$options}} argument can be used to control the way the input is converted.

|{{Error|BXCS0001parse|#Errors}} the specified input cannot be parsedas CSV document.<br/>{{Error|options|#Errors}} the specified options are conflicting.

|{{Func|csv:serialize|$input as nodeitem()?|xs:string}}<br/>{{Func|csv:serialize|$input as nodeitem()?, $options as map(xs:string, item()*)?|xs:string}}

|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.

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

<pre classsyntaxhighlight lang="brush:xml">

</presyntaxhighlight>

<pre classsyntaxhighlight lang="brush:xquery">

</presyntaxhighlight>

<pre classsyntaxhighlight lang="brush:xml">

</presyntaxhighlight>

<pre classsyntaxhighlight lang="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</presyntaxhighlight>

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

<pre classsyntaxhighlight lang="brush:xquery">let $text := "``[Name;,City" || outJack,ChicagoJack,WashingtonJohn,New York]``let $options := map { 'format':nl() || "John;Newton" || out'xquery', 'header':nltrue() || "Jack;Oldtown"}let $options csv := <csv:parse($text, $options>)return ( <csv 'Distinct values:separator value=';'/>, <csv let $records :format value=$csv('maprecords'/>) < for $name at $pos in $csv:header value=('yesnames'/>)?* </csvlet $values :options>= $records?($pos) return csv( '* ' || $name || ':parse' || string-join(distinct-values($textvalues), ', $options') ))</presyntaxhighlight>

<pre classsyntaxhighlight lang="brush:xmlxquery">{ 1Distinct values: { "City"* Name: "Newton"Jack, "Name": "John" }, 2: { "* City": "Oldtown"Chicago, Washington, "Name": "Jack" }}New York</presyntaxhighlight>

|{{Code|BXCS0001parse}}

|{{Code|BXCS0002serialize}}