Dark Horse programmer--oc Language Basic Grammar Knowledge Foundation

1. Structure: Nsrange, Nspoint (Cgpoint), Nssize (cgsize), Nsrect (CGRect)

Nsrange: Represents a range with two member variables: location, length

For example: @ "I love You" to find out the range of love

int main ()

{

Nsrange r1= nsmakerange{2,4};

return 0;

}

Example: Find out the range of a string in str

NSString *str = @ "I love You";

Nsranger r2 = [str rangeofstring: @ "VE"];

NSLog (@ "loc =%ld,len=%ld", r2.location,r2.length);

Point, Size, rect, and range are all similar usages

Cgpoint P1 = Cgpointmake (20,20);//Represents a coordinate

cgsize S1 = cgsizemake (200,100);//indicates length and width

CGRect r1 = CGRectMake (0,0,100,122);//Represents a block in a coordinate

2. String: NSString nsmutablestring

NSString: Immutable string, once assigned, cannot change the object's contents in the future.

Nsmutablestring: variable string, want to increase later, want to delete the deletion

For example:

int main ()

{

nsmutablestring *s1 = [nsmutablestring stringWithFormat: @ "My age is 10"] '

Stitch it in the back.

[S1 appendString: @ "11 12 13"]; The result is my 10 11 12 13

Get the scope of IS

Nsrange range = [S1 rangeofstring: @ "is"];

[S1 deletecharactersinrange:range];//Delete the contents of range

NSLog (@ "s1=%@", S1); Result my age 10 11 12 13

}

3. Array: Nsarray Nsmutablearray

Nsarray: Non-variable group

1. Quickly create a Nsarray object

Nsarray *array = @[@ "Jack" @ "Rose" @ "Jim"];

2. Quick access to elements in an array

NSLog (@ "%@", array[2]);//The compiler encounters this line of code, which is automatically translated as: NSLog (@ "%@", [Array object atindex:2]);

3. Fast traversal of arrays

ID obj represents each element in an array

for (id obj in Array)

{

Find the position of the obj element in the array

Nsuinteger i = [array indexofobject:obj];

NSLog (@ "%d-%d", i,obj);

}

4. Using block traversal

Each time a block is traversed, it is called once, and the current element and index position are passed as parameters to the block

[Array Enumerateobjectsusingblock: ^ (id obj,nsuinteger idx, BOOL *p)

{

NSLog (@ "%ld-%ld", idx,obj);

if (idx = = 1)

{

Stop traversal

*stop = YES;

}

}

];

Nsmutablearray: Variable Array

Nsmutablearray *array = [Nsmutablearray arraywithobjects:@ "Jack" @ "Rose", nil];

adding elements

[Array Addobject:[[person alloc] init];

[Array addobject:@ "Jake"];

Delete all elements

[Array removeallobjects];

Delete an Established object

[Array removeobject:@ "Jack"];

[Array removeobjectatindex:0];

/*

Note: @[@ "Jack" @ "Rose"]: can only be used to create immutable variable groups Nsarray

Error wording:

Nsmutablearray *array = @[@ "Jack" @ "Rose"];

[Array AddObject: @ "Jim"];

Nsmutablearray and AddObject are mutable arrays and @[@ "Jack" @ "Rose" is an immutable group

*/

Comparison of 4.NSSet and Nsarray

1. Common denominator: ① are all collections and can hold multiple OC objects

② can only exist OC objects and cannot hold non-OC objects

The ③ itself is immutable and has a mutable subclass

2. Different points: Nsarray ordered Nsset disorder

5: The Application of the dictionary

1. Dictionary: Nsdictionary nsmutabledictionary

1.NSDictionary

Key--value

Index--Content

It's all stored in key-value pairs.

Nsdictionary *dict = @

{

@ "name": @ "Jack",

@ "Address": @ "Beijing",

@ "QQ": @ "123543", nil

}

ID obj = [dict objectforkey: @ "QQ"];

NSLog (@ "%@", obj);//print Result: 123543

ID obj = dict[@ "QQ"];

The number of key-value pairs returned

NSLog (@ "%ld", Obj.count);

2.NSMutableDictionary

int main ()

{

Nsmutabledictionary *dict = [Nsmutabledictionary dictionary];

To add a key-value pair

[Dict setobject:@ "Jake" forkey:@ "name"];

[Dict setobject:@ "Address" forkey:@ "Beijing"];

[Dict setobject:@ "Jack" forkey:@ "name"];//the same key, the back of which will overwrite the previous one, then the 2 key-value pairs now

Removing key-value pairs

[Dict removeobjectforkey @ "name"];

NSString *str = dict[@ "name"];

NSLog (@ "%@", str);//print Result: Rose

}

Using block traversal

[Dict Enumeratekeysandobjectsusingblock:

^ (id key,id obj,bool *stop)

{

NSLog (@ "%@--%@", key,obj);

}

];

Dark Horse programmer--oc Language Basic Grammar Knowledge Foundation