Nsarray Basic Usage

Nsarray Array

class method to create an array (empty array, no meaning)
Nsarray *array = [Nsarray array];

An instance method creates an array (an empty array)
Nsarray *array1 = [[Nsarray alloc]init];

Create an array and initialize the element nil to indicate the end of the array
Nsarray *array2 = [Nsarray arraywithobjects:@ "Wukong", @ "eight commandments", @ "baigujing", nil];

Use an array to create a new array (equivalent to an array copy)
Nsarray *array3 = [Nsarray arraywitharray:array2];


Quickly create
Nsarray *array4 = @[@ "1", @ "ret", @ "FRSGDFH"];

Instance method specifies the object creation array
Nsarray *array5 = [[Nsarray alloc]initwithobjects:@ "3", @ "JDS", @ "F", Nil];

Number of array elements
NSLog (@ "%ld", [Array5 Count]);

Accessing array elements
NSLog (@ "%@", [Array5 objectatindex:1]);
NSLog (@ "%@", array5[1]);

Whether to include an object (the IsEqual method that invokes the object)
BOOL iscontain = [Array containsobject:@ "1"];

String Cut Array
NSString *string7 = @ "20|http://www.baidu.com";
Nsarray *a = [String7 componentsseparatedbystring:@ "|"];
for (int i = 0; i < [a count]; i++) {
NSLog (@ "%@", A[i]);
}



Variable groups (be sure to initialize)
Create a mutable array (cannot be created as quickly as Nsarray)
Nsmutablearray *marray = [Nsmutablearray array];
Nsmutablearray *mutablearray1 = [[nsmutablearray alloc]init];//instance variable initialization
The array can hold the number of elements when created
Nsmutablearray *arr = [Nsmutablearray arraywithcapacity:10];



Adding an array element
[MutableArray1 addobject:@ "Xiaobai"];
adding multiple array elements
Mutablearray1.array = @[@ "ds", @ "3", @ "RT"];
Inserts an element in the specified subscript
[MutableArray1 insertobject:@ "Xiaohei" atindex:1];

Delete element at end of array
[MutableArray1 Removelastobject];

Delete all elements
[MutableArray1 removeallobjects];

Delete array corresponding elements based on element object (compare by IsEqual method)
[MutableArray1 removeobject:@ "Xiaohei"];

Delete the corresponding element according to the array element subscript
[MutableArray1 removeobjectatindex:0];

Iterating through an array
Nsarray *array6 = [Nsarray arraywithobjects:@ "Naruto", @ "Luffy", @ "Sasuke", @ "Zoro", @ "Conan", @ "Kakashi", nil];
for (int i = 0; i < [Array6 count]; i++) {
NSLog (@ "%@", [Array6 objectatindex:i]);
NSLog (@ "%@", Array6[i]);
}

For (NSString *str in Array6) {
NSLog (@ "%@", str);
}

Gets the first element of the array
NSLog (@ "%@", [Array6 Firstobject]);

Gets the last element of the array
NSLog (@ "%@", [Array6 Lastobject]);



Array of string turns
NSString *string = @ "1 2 3 4 5 6";
Use a string to split the original string into an array
Nsarray *ARRAY14 = [string componentsseparatedbystring:@ ""];

NSLog (@ "%@", ARRAY14);
Assemble the array string
NSString *str = [Array componentsjoinedbystring:@ "-"];
NSLog (@ "%@", str);



Let all elements in the array execute a method
[Array makeobjectsperformselector: @selector (bark)];
[Array makeobjectsperformselector: @selector (Eat:) withobject:@ "Bone"];

Iterating through an array
Use the normal for
Nsarray *ARR3 = @[@ "Re", @ "FD", @ "S"];

for (int index = 0; index < array.count; index++) {
NSString *sss = Array[index];
NSLog (@ "%@", SSS);
}
Use Add for (most commonly used)

For (NSString *str in arr) {

NSLog (@ "%@", str);

}

Through the enumerator
Nsenumerator *enumer = [arr objectenumerator];
NSString *newdog;
while (Newdog = [Enumer Nextobject]) {
NSLog (@ "%@", Newdog);
}

by block mode
The IDX represents this element in the array index
Stop is set to Yes so it doesn't traverse backwards.
[Arr enumerateobjectsusingblock:^ (NSString * dog, Nsuinteger idx, BOOL *stop) {
NSLog (@ "%@-%zd", DOG,IDX);
if (idx = = 2) {
*stop = YES;
}
}];


Array sorting
Using the comparator (block)
Array = [Array Sortedarrayusingcomparator:^nscomparisonresult (Czdog * obj1, Czdog * obj2) {
//
if (obj1.age = = obj2.age) {
return [Obj1.name Compare:obj2.name];
}else if (Obj1.age > Obj2.age) {
return nsordereddescending;//Descending
}else{
return nsorderedascending;//Ascending
//            }
//
return [Obj1.name Compare:obj2.name];
//        }];
NSLog (@ "%@", array);
Property Descriptor Comparison
Nssortdescriptor *DESC1 = [nssortdescriptor sortdescriptorwithkey:@ "age" ascending:yes];
Nssortdescriptor *DESC2 = [nssortdescriptor sortdescriptorwithkey:@ "name" Ascending:yes];

Array = [array sortedarrayusingdescriptors:@[desc1,desc2]];
NSLog (@ "%@", array);

Nsarray Basic Usage