Objective C 2.0, Foundation Framework Quick Reference

Data Type Conversion Rules
The Objective-C compiler adheres to very strict rules when it comes to evaluating expressions that consist of different data types.

The following summarizes the order in which conversions take place in the evaluation of two operands in an expression:

1. If either operand is of type long double, the other is converted to long double, and that is the type of the result.

2. If either operand is of type double, the other is converted to double, and that is the type of the result.

3. If either operand is of type float, the other is converted to float, and that is the type of the result.

4. If either operand is of type _Bool, char, short int, or bit field,[1] or of an enumerated data type, it is converted to int.

5. If either operand is of type long long int, the other is converted to long long int, and that is the type of the result.

6. If either operand is of type long int, the other is converted to long int, and that is the type of the result.

7. If this step is reached, both operands are of type int, and that is the type of the result.

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Common NSString Methods
Method	Description
+(id) stringWithContentsOfFile: path encoding: enc error: err	Creates a new string and sets it to the path contents of a file specified by path using character encoding enc, returning error in err if non-nil
+(id) stringWithContentsOfURL: url encoding: enc error: err	Creates a new string and sets it to the contents of url using character encoding enc, returning error in err if non-nil
+(id) string	Creates a new empty string
+(id) stringWithString: nsstring	Creates a new string, setting it to nsstring
-(id) initWithString: nsstring	Sets a newly allocated string to nsstring
-(id) initWithContentsOfFile: path encoding: enc error: err	Sets a string to the contents of a file specified by path
-(id) initWithContentsOfURL: url encoding enc error: err	Sets a string to the contents of url (NSURL *) url using character encoding enc, returning error in err if non-nil
-(NSUInteger) length	Returns the number of characters in the string
-(unichar) characterAtIndex: i	Returns the Unicode character at index i
-(NSString *) substringFromIndex: i	Returns a substring from the character at i to the end
-(NSString *) substringWithRange: range	Returns a substring based on a specified range
-(NSString *) substringToIndex: i	Returns a substring from the start of the string up to the character at index i
-(NSComparator *) caseInsensitiveCompare: nsstring	Compares two strings, ignoring case
-(NSComparator *) compare: nsstring	Compares two strings
-(BOOL) hasPrefix: nsstring	Tests whether a string begins with nsstring
-(BOOL) hasSuffix: nsstring	Tests whether a string ends with nsstring
-(BOOL) isEqualToString: nsstring	Tests whether two strings are equal
-(NSString *) capitalizedString	Returns a string with the first letter of every word capitalized (and the remaining letters in each word converted to lower case)
-(NSString *) lowercaseString	Returns a string converted to lower case
-(NSString *) uppercaseString	Returns a string converted to upper case
-(const char *) UTF8String	Returns a string converted to a UTF-8 C-style character string
-(double) doubleValue	Returns a string converted to a double
-(float) floatValue	Returns a string converted to a floating value
-(NSInteger) integerValue	Returns a string converted to an NSInteger integer
-(int) intValue	Returns a string converted to an integer

Common NSMutableString Methods
Method	Description
+(id) stringWithCapacity: size	Creates a string initially containing size characters.
-(id) initWithCapacity: size	Initializes a string with an initial capacity of size characters.
-(void) setString: nsstring	Sets a string to nsstring.
-(void) appendString: nsstring	Appends nsstring to the end of the receiver.
-(void) deleteCharactersInRange: range	Deletes characters in a specified range.
-(void) insertString: nstring atIndex: i	Inserts nsstring into the receiver starting at index i.
-(void) replaceCharactersInRange: range withString: nsstring	Replaces characters in a specified range with nsstring.
-(void) replaceOccurrencesOf String: nsstring withString: nsstring2 options: opts range: range	Replaces all occurrences of nsstring with nsstring2 within a specified range and according to options opts. Options can include a bitwise-ORed combination of NSBackwardsSearch (the search starts from the end of range), NSAnchoredSearch (nsstring must match from the beginning of the range only), NSLiteralSearch (performs a byte-by-byte comparison), and NSCaseInsensitiveSearch.

Common NSArray Methods
Method	Description
+(id) arrayWithObjects: obj1, obj2, ... nil	Creates a new array with obj1, obj2, ... as its elements
-(BOOL) containsObject: obj	Determines whether the array contains obj (uses the isEqual: method)
-(NSUInteger) count	Indicates the number of elements in the array
-(NSUInteger) indexOfObject: obj	Specifies the index number of the first element that contains obj (uses the isEqual: method)
-(id) objectAtIndex: i	Indicates the object stored in element i
-(void) makeObjectsPerform Selector: (SEL) selector	Sends the message indicated by selector to every element of the array
-(NSArray *) sortedArrayUsing Selector: (SEL) selector	Sorts the array according to the comparison method specified by selector
-(BOOL) writeToFile: path automically: (BOOL) flag	Writes the array to the specified file, creating a temporary file first if flag is YES

Common NSMutableArray Methods
Method	Description
+(id) array	Creates an empty array
+(id) arrayWithCapacity: size	Creates an array with a specified initial size
-(id) initWithCapacity: size	Initializes a newly allocated array with a specified initial size
-(void) addObject: obj	Adds obj to the end of the array
-(void) insertObject: obj atIndex: i	Inserts obj into element i of the array
-(void) replaceObjectAtIndex: i withObject: obj	Replaces element i of the array with obj
-(void) removeObject: obj	Removes all occurrences of obj from the array
-(void) removeObjectAtIndex: i	Removes element i from the array, moving down elements i+1 through the end of the array
-(void) sortUsingSelector: (SEL) selector	Sorts the array based on the comparison method indicated by selector

Common NSDictionary Methods
Method	Description
+(id) dictionaryWithObjectsAndKeys: obj1, key1, obj2, key2, ..., nil	Creates a dictionary with key-object pairs {key1, obj1}, {key2, obj2}, ...
-(id) initWithObjectsAndKeys: obj1, key1, obj2, key2,..., nil	Initializes a newly allocated dictionary with key-object pairs {key1, obj1}, {key2, obj2}, ...
-(unsigned int) count	Returns the number of entries in the dictionary
-(NSEnumerator *) keyEnumerator	Returns an NSEnumerator object for all the keys in the dictionary
-(NSArray *) keysSortedByValueUsingSelector: (SEL) selector	Returns an array of keys in the dictionary sorted according to the comparison method selector specifies
-(NSEnumerator *) objectEnumerator	Returns an NSEnumerator object for all the values in the dictionary
-(id) objectForKey: key	Returns the object for the specified key

Common NSMutableDictionary Methods
Method	Description
+(id) dictionaryWithCapacity: size	Creates a mutable dictionary with an initial specified size
-(id) initWithCapacity: size	Initializes a newly allocated dictionary to be of an initial specified size
-(void) removeAllObjects	Removes all entries from the dictionary
-(void) removeObjectForKey: key	Removes the entry for the specified key from the dictionary
-(void) setObject: obj forKey: key	Adds obj to the dictionary for the key key and replaces the value if key already exists

Common NSSet Methods
Method	Description
+(id) setWithObjects: obj1, obj2, ..., nil	Creates a new set from the list of objects
-(id) initWithObjects: obj1, obj2, ..., nil	Initializes a newly allocated set with a list of objects
-(NSUInteger) count	Returns the number of members in the set
-(BOOL) containsObject: obj	Determines whether the set contains obj
-(BOOL) member: obj	Determines whether the set contains obj (using the isEqual: method)
-(NSEnumerator *) objectEnumerator	Returns an NSEnumerator object for all the objects in the set
-(BOOL) isSubsetOfSet: nsset	Determines whether every member of the receiver is present in nsset
-(BOOL) intersectsSet: nsset	Determines whether at least one member of the receiver appears in nsset
-(BOOL) isEqualToSet: nsset	Determines whether the two sets are equal

Common NSMutableSet Methods
Method	Description
-(id) setWithCapacity: size	Creates a new set with an initial capacity to store size members
-(id) initWithCapacity: size	Sets the initial capacity of a newly allocated set to size members
-(void) addObject: obj	Adds obj to the set
-(void) removeObject: obj	Removes obj from the set
-(void) removeAllObjects	Removes all members of the receiver
-(void) unionSet: nsset	Adds each member of nsset to the receiver
-(void) minusSet: nsset	Removes all members of nsset from the receiver
-(void) intersectSet: nsset	Removes all members from the receiver that are not also in nsset

Common NSFileManager Methods
Method	Description
-(NSData *) contentsAtPath: path	Reads data from a file
-(NSData *) createFileAtPath: path contents: (NSData *) data attributes: attr	Writes data to a file
-(BOOL) removeFileAtPath: path handler: handler	Removes a file
-(BOOL) movePath: from toPath: to handler: handler	Renames or moves a file (to cannot already exist)
-(BOOL) copyPath: from toPath: to handler: handler	Copies a file (to cannot already exist)
-(BOOL) contentsEqualAtPath: path1 andPath: path2	Compares contents of two files
-(BOOL) fileExistsAtPath: path	Tests for file existence
-(BOOL) isReadableFileAtPath: path	Tests whether file exists and can be read
-(BOOL) isWritableFileAtPath: path	Tests whether file exists and can be written
-(NSDictionary *) fileAttributesAtPath: path traverseLink: (BOOL) flag	Gets attributes for file
-(BOOL) changeFileAttributes: attr atPath: path	Changes file attributes

Common Path Utility Methods
Method	Description
+(NSString *) pathWithComponents: components	Constructs a valid path from elements in components
-(NSArray *) pathComponents	Deconstructs a path into its constituent components
-(NSString *) lastPathComponent	Extracts the last component in a path
-(NSString *) pathExtension	Extracts the extension from the last component in a path
-(NSString *) stringByAppendingPathComponent: path	Adds path to the end of an existing path
-(NSString *) stringByAppendingPathExtension: ext	Adds the specified extension to the last component in the path
-(NSString *) stringByDeletingLastPathComponent	Removes the last path component
-(NSString *) stringByDeletingPathExtension	Removes the extension from the last path component
-(NSString *) stringByExpandingTildeInPath	Expands any tildes in the path to the user's home directory (~) or a specified user's home directory (~user)
-(NSString *) stringByResolvingSymlinksInPath	Attempts to resolve symbolic links in the path
-(NSString *) stringByStandardizingPath	Standardizes a path by attempting to resolve ~, ..(parent directory), .(current directory), and symbolic links

Common Resources Path for iPhone

NSBundle Select all


NSString *myinfoplist = [ [ NSString alloc ] initWithFormat: @"%@/Info.plist", [[NSBundle mainBundle] resourcePath] ];
NSLog (@"Documents Folder is %@",[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"]);
NSString *myFile = [ [ NSString alloc ] initWithFormat: @"%@/Documents/file.db", NSHomeDirectory() ];

NSDirectoryEnumerator *dirEnum;
NSString *file;
dirEnum = [ [ NSFileManager defaultManager ] enumeratorAtPath:NSHomeDirectory()];
while (file = [ dirEnum nextObject ]) {
NSLog(@"%@",[NSHomeDirectory() stringByAppendingPathComponent:file]);
/*
Documents/
Library/
Preferences/
MyApp.app/
*/
}