"Objective-c Study record" 23rd Day

Array Class :

Ordered collection

Not variable

An array in OC is a container that can manage a series of elements in an orderly manner , with different element types, but must be object types.

Initialization Method :

1.initWithObjects:

2. Convenience Builder

3. Literal.

1 nsarray *array = @[@ "SF"@ "QOP"@ " ST " @" PANDA "];

Original (Core) method :

1.count. Number of elements in an array

2.objectAtIndex. Get array elements by subscript

Common Methods :

1.containsObjects:. Determines whether an element is contained in an array, returns a Boolean value

2.indexOfObject:. Gets the subscript of the element in the array, based on the element, and returns Nsuinteger

3.componentsSeparatedByString:. This method is called by a string object , splits the string as a separator, and returns the substring to the array

4.componetsJoinedByString:. This method is called by the array object , joins the element in the array as a connector, and returns the concatenated string

variable :

Initialization Method :

1.initWithCapacity:. Like a mutable string, a parameter allocates space because the variable array itself can be resized, so the array depends on the situation

2. Convenience Builder

3. Literal

1 nsmutablearray *array = [@[@"ES"@"VS"@ " NA " @" CM "] Mutablecopy];

This way can also be initialized for variable strings, Mutablecopy is the protocol method in the Mutablecopywithzone: The return value, specifically what is not very clear, the API so write

Common Methods :

1.addObject:. Adding elements to a mutable array

2.insertobject:atindex:. Inserts a new element into the variable array at the specified position

3. Remove the element:

A.removeobject:. parameter is the object name

B.removeobjectatindex:. Delete an element based on an incoming subscript

C.removelastobject:. Delete the last element in an array

D.removeallobjects:. Delete all elements in an array

4.replaceobjectatindex:withobject:. Replace the element to which the first parameter is indexed with the second argument

5.exchangeobjectatindex:withobjectatindex:. Exchange two elements according to subscript

Dictionary class :

Unordered collection, each object is a pair of key-value pairs, by key access element ,key and value must be the object type .

Not variable

Initialization Method :

1.initWithObjectsAndKeys:

2. Convenience Builder

3. Literal

1 nsdictionary *dict = @{@ "Key1": @ "value1", @ "Key2": @ "value2" @ "Key3": @ "Value3" @ "Key4": @ "Value4" };

It is important to note that the convenience constructor as well as the Init method are the values in the previous key after , and the literal is the key before the value .

Common Methods :

1.count. Gets the number of key-value pairs in the dictionary

2.allKeys. Gets all the key values returned to an array

3.allValues. Gets all the values returned to an array

4.objectForKey:. Gets a value in the dictionary by key

Variable

Initialization Method :

1.initWithCapacity:. parameter is the allocated capacity

2. Convenience Builder

3. Literal

1Nsmutabledictionary *mdict = [@{@"Key1":@"value1",@"Key2":@"value2",@"Key3":@"Value3",@"Key4":@"Value4"} Mutablecopy];

Common Methods :

1.setobject:forkey:. Increase key-value pairs

2.removeObjectForkey:. Delete key value pairs according to key

3.removeAllObjects:. Remove all key-value pairs

4.setobject:forkey:. Modify the key-value pairs and add the key-value pairs as well, if the key already exists then modify it, and the new one does not exist

---------to Be Continued---------

"Objective-c Study record" 23rd Day