Use of literal syntax--ios

When using OC, nsstring,nsnumber,nsarray,nsdictionary is often used, and the following is the use of their literal syntax.

(1) Literal value

It is sometimes necessary to block integers, floating-point numbers, and Boolean values into OC objects

General wording:

NSNumber *num = [NSNumber numberwithint:1];

Use literal syntax:

NSNumber *num = @1;

Other types use literal syntax:

NSNumber *[email protected];

NSNumber *[email protected];

NSNumber *[email protected];

NSNumber *[email protected];

NSNumber *[email protected] ' a ';

The literal also applies to the following expression:

int x=5;

Float y =6.15f;

NSNumber *[email protected] (x*y);

(2) Literal array

General wording:

Nsarray *animals=[nsarray arraywithobject:@ "cat", @ "dog", @ "mouse", nil];

Use literal syntax:

Nsarray *[email protected][@ "cat", @ "dog", @ "Mouse"];

Operation of the array

General wording:

NSString *dog=[animals Objectatindex:1];

Use literal:

NSString *dog=animals[1];

(3) Literal dictionary

General wording:

Nsdictionary *persondata=[nsdictionarydictionarywithobjectsandkeys:@ "Matt" @ "FirstName", @ "Galloway", @ "LastName" , [NSNumber numberwithint:28],@ "age", nil];

Use literal:

Nsdictionary *[email protected]{@ "firstName": @ "Matt" @ "LastName": @ "Galloway" @ "Age": @28};

Operation of the Dictionary

General wording:

NSString *lastname=[persondata objectforkey:@ "LastName"];

Use literal:

NSString *lastname=persondata[@ "LastName"];

(4) Variable groups and dictionaries

By removing the label operation, you can access an element in the array that corresponds to a key in the index or dictionary. If the array and the Dictionary object are mutable, the element values can also be modified by subscript.

General wording:

[Mutablearray replaceobjectatindex:1 withobject:@ "Dog"];

[Mutabledictionary setobject:@ "Galloway" forkey:@ "LastName"];

Use literal:

Mutablearray[1][email protected] "dog";

mutabledictionary[@ "LastName"][email protected] "Galloway";

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

Use of literal syntax--ios