stringByAppendingPathComponent及他的删除函数 等系列函数

- (NSString *)stringByAppendingPathComponent:(NSString *)aString

aString is “scratch.tiff”:

Receiver’s String Value

Resulting String

“/tmp”

“/tmp/scratch.tiff”

“/tmp/”

“/tmp/scratch.tiff”

“/”

“/scratch.tiff”

“” (an empty string)

“scratch.tiff”

- (NSString *)stringByDeletingLastPathComponent

Receiver’s String Value

Resulting String

“/tmp/scratch.tiff”

“/tmp”

“/tmp/lock/”

“/tmp”

“/tmp/”

“/”

“/tmp”

“/”

“/”

“/”

“scratch.tiff”

“” (an empty string)

- (NSString *)stringByAppendingPathExtension:(NSString *)ext

ext is"tiff"

Receiver’s String Value

Resulting String

“/tmp/scratch.old”

“/tmp/scratch.old.tiff”

“/tmp/scratch.”

“/tmp/scratch..tiff”

“/tmp/”

“/tmp.tiff”

“scratch”

“scratch.tiff”

- (NSString *)stringByDeletingPathExtension




Receiver’s String Value

Resulting String

“/tmp/scratch.tiff”

“/tmp/scratch”

“/tmp/”

“/tmp”

“scratch.bundle/”

“scratch”

“scratch..tiff”

“scratch.”

“.tiff”

“.tiff”

“/”

“/”

- (NSString *)stringByAppendingString:(NSString *)aString

aString

The string to append to the receiver. This value must not be nil.

NSString *errorTag = @"Error: ";

NSString *errorString = @"premature end of file.";

NSString *errorMessage = [errorTag stringByAppendingString:errorString];

produces the string “Error:premature end of file.”.