Learn Objective-C: Escape Sequences and Format Specifiers
NSLog, and its corresponding C function printf(), use escape sequences to print certain characters that are “invisible.” For iOS, include:
| Sequence | Meaning | 
|---|---|
\b | 
      backspace | 
\f | 
      Form Feed | 
\n | 
      Newline | 
\t | 
      Horizontal Tab | 
\v | 
      Vertical Tab | 
\\ | 
      Backslash | 
\' | 
      Single Quote | 
\" | 
      Double Quote | 
\? | 
      Question Mark | 
There are others, such as \a for Alert, but they are rarely used, and don’t make an effect.
Format specifiers, however, are the percent character, followed by a letter, such as %d or %f that tell NSLog or printf() to print the value or result of a variable, value, and/or expression.
Click here for a list of C format specifiers.
Just think of them as types of placeholders, each designed to represent a different value.
This post is part of the Learn Objective-C in 24 Days course.