# object(byApplyingXSLTString:arguments:) Applies the XSLT pattern rules and templates (specified as a string) to the receiver and returns a document object containing transformed XML or HTML markup. ``` func object(byApplyingXSLTString xslt: String, arguments: [String : String]?) throws -> Any ``` ## Parameters `xslt` A string object containing the XSLT pattern rules and templates. `arguments` A dictionary containing [`NSString`](/documentation/Foundation/NSString) key-value pairs that are passed as runtime parameters to the XSLT processor. Pass in `nil` if you have no parameters to pass. > Note: > Several XML websites discuss XSLT parameters, including O’Reilly Media’s . ## Return Value Depending on intended output, the method returns an `NSXMLDocument` object *or* an [`NSData`](/documentation/Foundation/NSData) data containing transformed XML or HTML markup. If the message is supposed to create plain text or RTF, then an `NSData` object is returned, otherwise an XML document object. The method returns `nil` if XSLT processing did not succeed. ## Discussion > Handling Errors in Swift: > In Swift, this method returns a nonoptional result and is marked with the `throws` keyword to indicate that it throws an error in cases of failure. > > You call this method in a `try` expression and handle any errors in the `catch` clauses of a `do` statement, as described in [Error Handling](https://docs.swift.org/swift-book/LanguageGuide/ErrorHandling.html) in [The Swift Programming Language](https://docs.swift.org/swift-book/) and `About Imported Cocoa Error Parameters`. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)