Ruby and Data Formats Parsing JSON JSON, short for JavaScript Object Notation, was designed as a human-readable format allowing arrays, hashes, numbers, and strings to be serialized as plain text to communicate data between programs, no matter what language they are written in. Designed partially as a reaction to the verboseness of XML, JSON is sparse both in the number of characters required and in the number of data types it supports. We briefly looked at using JSON as a way to store Ruby data in Section 10.2.5, “Persisting Data with JSON” of Chapter 10, “I/O and Data Storage.” In this section, we’ll look at how to parse and manipulate the type of JSON data that might be provided by a website API. Underworld evolution full movie free download torrent. Before we do that, though, let’ s review how to parse a string or file containing JSON data into a Ruby hash: What JSON calls an “object” corresponds almost perfectly to what we in Ruby-land know as a hash. Meanwhile, JSON contains several other easily recognizable types: arrays, strings, and numbers. ![]() JSON (including the strings contained inside it) is always encoded as UTF-8, and the only other types it is able to encode are true, false, and null (or nil in Ruby). Navigating JSON Data Once the JSON has been parsed, the nested hashes and arrays that are returned can be navigated to extract the specific data required. T o illustrate this, we’ll use some JSON data provided by the GitHub public API: In the preceding code, we are using the open-uri library for convenience. This is explained in greater detail in Chapter 18, “Network Programming”; for now, just be aware that it enables us to use the open method on a URI much as if it were a simple file. Using open-uri, we download a string that contains a JSON array of the GitHub accounts of contributors to the main Ruby interpreter. (Many contributors who lack GitHub accounts are not included in this list.) Parsing the JSON gives us an array of hashes, with each hash containing information about one particular contributor, with keys including login, id, url, and contributions, among others. Then, we use pp, the “prettyprint” library, to print the hash of attributes for the first contributor. (Every attribute is printed by pp, but we’ve elided some of them here to save space.) Next, we reverse-sort the list by the number of contributions so that the hashes are ordered from most commits to least commits. Finally, we map the sorted hashes of contributor information into just their login (or username) and print them as a commaseparated list. Most real-world uses of JSON data are similar to this one: Write some code to fetch the data, parse the data into a native Ruby hash or array, and then find the array items or hash keys that contain the data you are interested in. Parsing XML (and HTML) XML, the eXtensible Markup Language, is a tag-based markup language. HTML, the HyperT ext Markup Language, is very similar (and, in fact, both XML and HTML are based on an earlier tag-based system called SGML). XML and HTML both rose to massive popularity in the 1990s, and are still used heavily today in development tools, program data storage and transfer, and all over the W eb. Jan 9, 2018 - Download Ruby, Rails ebooks [birdwin] torrent or any other torrent from the Other E-books. Direct download via magnet link. The Ruby Way Pdf. ![]() In XML and HTML, every element is named, and the entire document is hierarchically structured. Although it is highly verbose, everything is written in plain text and can be read by a human being directly, if needed. Another advantage over formats from the 70s and 80s is that XML allows variable-length data, rather than requiring each data field to fit into a specific number of bytes. RCBO’s) designed to comply to the 17th Edition Amendment 3 of the wiring regulations (BS 7671:2008). Consumer unit doors must be top hinged to ensure the door is closed when the unit is not in use. Can someone settle an arguement me and a work pal were having today please? Its with regards labels/stickers that you put on a consumer unit. There was a Y2K issue solely because most of our legacy data was stored and manipulated in fixed-length formats. So, although it has shortcomings, XML also has its uses. In Ruby, the most common way to read, manipulate, and write XML or HTML is with the Nokogiri gem. The gem provides a Ruby interface (also called binding) for the libXML2 library, which is written in C. Nokogiri has two primary APIs, which could be called document based and str eam based. W e’ll look at both approaches. Ruby and Web Applications HTTP Servers HTTP servers make up a huge proportion of the programs in service today.
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