# string(for:) The default implementation of this method raises an exception. ``` func string(for obj: Any?) -> String? ``` ## Parameters `obj` The object for which a textual representation is returned. ## Return Value An `NSString` object that textually represents `object` for display. Returns `nil` if `object` is not of the correct class. ## Discussion When implementing a subclass, return the `NSString` object that textually represents the cell’s object for display and—if [`editingString(for:)`](/documentation/Foundation/Formatter/editingString(for:)) is unimplemented—for editing. First test the passed-in object to see if it’s of the correct class. If it isn’t, return `nil`; but if it is of the right class, return a properly formatted and, if necessary, localized string. (See the specification of the [`NSString`](/documentation/Foundation/NSString) class for formatting and localizing details.) The following implementation (which is paired with the [`getObjectValue(_:for:errorDescription:)`](/documentation/Foundation/Formatter/getObjectValue(_:for:errorDescription:)) example above) prefixes a two-digit float representation with a dollar sign: ```objc - (NSString *)stringForObjectValue:(id)anObject { if (![anObject isKindOfClass:[NSNumber class]]) { return nil; } return [NSString stringWithFormat:@"$%.2f", [anObject floatValue]]; } ``` ## See Also [Data Formatting Guide](https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/DataFormatting/DataFormatting.html#//apple_ref/doc/uid/10000029i) [`getObjectValue(_:for:errorDescription:)`](/documentation/Foundation/Formatter/getObjectValue(_:for:errorDescription:)) The default implementation of this method raises an exception. --- 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)