NSString(StringSprintf)

Implementation of sprintf for NSString

Extends Class: NSString
Declared In: StringSprintf.h

Discussion

This category adds a single method, sprintf:, that implements formatted strings in the manner of C's standard library function.

Methods

-sprintf:

sprintf:

- (NSString*) sprintf:(NSArray*)values;

Discussion

Implements the standard C function sprintf, using the receiver as the format string, and the elements of values as values to format. Returns a new string containing the output. sprintf: will throw an exception if too many or not enough values are supplied in the values argument.

The standard flags - -, +, (space), and # are supported, as are the width and precision modifiers (including using * to indicate that the width should be taken from the next value in the array).

sprintf: implements the following argument formats:

s: Interprets the value as a string, and sends it the message cStringUsingEncoding:NSUTF8Encoding to produce a character string. Note: unlike the standard C printf, width and precision modifiers for strings count the number of characters, not the number of bytes.
@: Similar to the use of %@ in the NSString class method stringWithFormat:. Sends the value a description message and inserts that string into the output.
e
E: Prints the result of doubleValue in scientific notation. Uses the stdlib sprintf function.
f: Prints the result of doubleValue as a floating-point number. Uses the stdlib sprintf function.
i
d: Prints the result of sending intValue to the receiver as a decimal integer.
o: Prints the result of sending intValue to the receiver as an unsigned octal integer.
x
X: Prints the result of sending intValue to the receiver as an unsigned hexadecimal integer.
c: Interprets the value as an integer (using intValue) that represents a Unicode codepoint, and prints the corresponding character. This method uses F-Script's -[NSNumber unicharToString] method.
p: Prints the pointer address of the value as an unsigned hexadecimal integer.

The following standard formats are not supported:

g - shortest of exponential or floating
u - unsigned decimal integer
n - return number of written characters

Additionally, the h, l, and L modifiers (used to indicate C's short, long, and long double data types) are not supported.