问题
What are these called in Objective C? @"%@" @"%d" @"%i"
回答1:
They are called format specifiers, could also be called 'placeholders in a string for the variables that will follow'.
https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Strings/Articles/formatSpecifiers.html
回答2:
They are NSString literals. More specifically, they look they are being used as formatting strings for printf style functions.
回答3:
I believe that they are called 'format placeholders', as suggested by this wikipedia article: http://en.wikipedia.org/wiki/Printf_format_string#Format_placeholders
来源：https://stackoverflow.com/questions/7906948/name-for-d-in-an-nsstring