mirror of
https://github.com/alexandrev/xslt-lab.git
synced 2026-09-20 04:23:16 +00:00
alexandrev-tibco
b9d58ff7e0
- 19 reference pages under /xslt/functions/ covering: xsl:value-of, xsl:for-each, xsl:for-each-group, xsl:function, xsl:iterate, last(), position(), count(), concat(), contains(), substring(), sum(), key(), current(), string-join(), tokenize(), matches(), replace(), format-date() - Each page: description, parameters table, return value, 2 runnable examples (input XML + stylesheet + output), notes, cross-links - New Hugo section with reference-specific layout (version badges, syntax block, "Try in Playground" CTA, parameters table styles) - Menu entry "Reference" → /xslt/functions/ - CSS: .ref-badge, .ref-syntax, .ref-index-list, .ref-try + table styles Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
116 lines
3.5 KiB
Markdown
116 lines
3.5 KiB
Markdown
---
|
|
title: "sum()"
|
|
description: "Returns the sum of the numeric values in a node-set or sequence, or a specified zero value for empty sequences."
|
|
date: 2026-04-18T00:00:00Z
|
|
version: "1.0"
|
|
versionLabel: "XSLT 1.0"
|
|
category: "numeric function"
|
|
syntax: "sum(node-set)"
|
|
tags: ["xslt", "reference", "xslt1", "xpath"]
|
|
---
|
|
|
|
## Description
|
|
|
|
`sum()` converts each node in a node-set to a number (using the XPath `number()` rules) and returns their total as a double. If any node cannot be converted to a number, its value is treated as `NaN`, and the entire result is `NaN`.
|
|
|
|
In XSLT 2.0+, `sum()` accepts any sequence of atomic values that can be added together. A second argument may be provided as a **zero value** to return when the sequence is empty (in XPath 1.0, `sum()` on an empty node-set returns `0`).
|
|
|
|
`sum()` is the standard way to compute totals over repeated elements, such as order amounts, quantities, or scores, without writing an explicit loop.
|
|
|
|
## Parameters
|
|
|
|
| Parameter | Type | Required | Description |
|
|
|-----------|------|----------|-------------|
|
|
| `node-set` | node-set / sequence | Yes | The nodes or items to sum. Each is converted to a number. |
|
|
| `zero` | atomic value | No | Value to return if the sequence is empty (XPath 2.0+). Defaults to `0`. |
|
|
|
|
## Return value
|
|
|
|
`xs:double` (XPath 1.0) or the type matching the input sequence (XPath 2.0+) — the numeric sum of all items.
|
|
|
|
## Examples
|
|
|
|
### Sum all child element values
|
|
|
|
**Input XML:**
|
|
```xml
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<invoice>
|
|
<line amount="29.99"/>
|
|
<line amount="14.50"/>
|
|
<line amount="5.00"/>
|
|
</invoice>
|
|
```
|
|
|
|
**Stylesheet:**
|
|
```xml
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
|
|
<xsl:output method="text"/>
|
|
|
|
<xsl:template match="/invoice">
|
|
<xsl:text>Total: </xsl:text>
|
|
<xsl:value-of select="sum(line/@amount)"/>
|
|
</xsl:template>
|
|
</xsl:stylesheet>
|
|
```
|
|
|
|
**Output:**
|
|
```
|
|
Total: 49.49
|
|
```
|
|
|
|
### Conditional sum (sum filtered values)
|
|
|
|
**Input XML:**
|
|
```xml
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<sales>
|
|
<sale region="North" amount="100"/>
|
|
<sale region="South" amount="250"/>
|
|
<sale region="North" amount="175"/>
|
|
<sale region="South" amount="80"/>
|
|
</sales>
|
|
```
|
|
|
|
**Stylesheet:**
|
|
```xml
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
|
|
<xsl:output method="xml" indent="yes"/>
|
|
|
|
<xsl:template match="/sales">
|
|
<totals>
|
|
<north><xsl:value-of select="sum(sale[@region='North']/@amount)"/></north>
|
|
<south><xsl:value-of select="sum(sale[@region='South']/@amount)"/></south>
|
|
</totals>
|
|
</xsl:template>
|
|
</xsl:stylesheet>
|
|
```
|
|
|
|
**Output:**
|
|
```xml
|
|
<totals>
|
|
<north>275</north>
|
|
<south>330</south>
|
|
</totals>
|
|
```
|
|
|
|
### Empty sequence with fallback (XSLT 2.0)
|
|
|
|
```xml
|
|
<!-- Returns 0 when there are no discount elements -->
|
|
<xsl:value-of select="sum(discount/@value, 0)"/>
|
|
```
|
|
|
|
## Notes
|
|
|
|
- Nodes that cannot be converted to a number (e.g., text like `"N/A"`) produce `NaN`, which propagates through the sum. Validate data or use `number()` with a fallback before summing.
|
|
- `sum()` on an empty node-set returns `0` in XPath 1.0. In XPath 2.0+, the second argument controls this behaviour.
|
|
- For an average, there is no built-in `avg()` in XPath 1.0. Compute it as `sum(nodes) div count(nodes)`. XPath 2.0+ provides `avg()`.
|
|
- `sum()` works on attribute nodes as well as element text nodes; the path `sum(items/item/@qty)` is valid.
|
|
|
|
## See also
|
|
|
|
- [count()](../xpath-count)
|