https://github.com/sjp/selectr

Translate CSS Selectors to XPath Expressions
https://github.com/sjp/selectr

Last synced: 3 months ago
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Translate CSS Selectors to XPath Expressions

• Host: GitHub
• URL: https://github.com/sjp/selectr
• Owner: sjp
• License: other
• Created: 2012-11-08T10:14:28.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2024-05-09T10:20:36.000Z (6 months ago)
• Last Synced: 2024-06-11T17:00:07.307Z (5 months ago)
• Language: R
• Size: 150 KB
• Stars: 52
• Watchers: 6
• Forks: 5
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

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README

        
# selectr

[![License (3-Clause BSD)](https://img.shields.io/badge/license-BSD%203--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause) [![GitHub Actions](https://github.com/sjp/selectr/actions/workflows/r.yml/badge.svg)](https://github.com/sjp/selectr/actions/workflows/r.yml) [![CRAN version](https://www.r-pkg.org/badges/version/selectr)](https://cran.r-project.org/package=selectr) [![codecov](https://codecov.io/gh/sjp/selectr/branch/master/graph/badge.svg)](https://codecov.io/gh/sjp/selectr) ![Downloads per month](https://cranlogs.r-pkg.org/badges/last-month/selectr)

selectr is a package which makes working with HTML and XML documents easier. It does this by performing translation of CSS selectors into XPath expressions so that you can query `XML` and `xml2` documents easily.

``` r

library(selectr)

xpath <- css_to_xpath("#selectr")

xpath

#> [1] "descendant-or-self::*[@id = 'selectr']"

```

## Installation

### Install the release version from CRAN

``` r

install.packages("selectr")

```

### Install the development version from GitHub

``` r

# install.packages("devtools")

devtools::install_github("sjp/selectr")

```

## Overview

The key functions in selectr are:

* Translate a CSS selector into an XPath expression with `css_to_xpath()`.

* Query an `XML` or `xml2` document with `querySelector()` and its variants.

    * Find the first matching node with `querySelector()`.

    * Find all matching nodes with `querySelectorAll()`.

    * Find the first matching node in a namespaced document with `querySelectorNS()`.

    * Find all matching nodes in a namespaced document with `querySelectorAllNS()`.

## Examples

Here is a simple example to demonstrate how to query an `XML` or `xml2` document with `querySelector()`.

``` r

library(selectr)

xmlText <- ''

library(XML)

doc <- xmlParse(xmlText)

querySelector(doc, "baz")

#> 

querySelectorAll(doc, "baz")

#> [[1]]

#> 

#>

#> [[2]]

#> 

#>

#> attr(,"class")

#> [1] "XMLNodeSet"

library(xml2)

doc <- read_xml(xmlText)

querySelector(doc, "baz")

#> {xml_node}

#> 

querySelectorAll(doc, "baz")

#> {xml_nodeset (2)}

#> [1] 

#> [2] 

```