# CFStringCreateByCombiningStrings(_:_:_:) Creates a single string from the individual CFString objects that comprise the elements of an array. ``` func CFStringCreateByCombiningStrings(_ alloc: CFAllocator!, _ theArray: CFArray!, _ separatorString: CFString!) -> CFString! ``` ## Parameters `alloc` The allocator to use to allocate memory for the new string. Pass `NULL` or [`kCFAllocatorDefault`](/documentation/CoreFoundation/kCFAllocatorDefault) to use the current default allocator. `theArray` An array of CFString objects to concatenate. This value should not be `NULL`. `separatorString` The string to insert between the substrings in the returned string. This value is commonly a whitespace character such as a tab or a newline (carriage return). If this value is not a valid CFString object, an assertion is raised. ## Return Value A string that contains a concatenation of the strings in `theArray` separated by `separatorString`. The order of the substrings in the string is identical to the order of the elements in `theArray`. ## Discussion If `theArray` is empty, returns an empty CFString object; if `theArray` contains one CFString object, that object is returned (without the separator string). Returns `NULL` if there was a problem in creating the string. Ownership follows the [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029). ## Discussion See also [`CFStringCreateArrayBySeparatingStrings(_:_:_:)`](/documentation/CoreFoundation/CFStringCreateArrayBySeparatingStrings(_:_:_:)). --- 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)