Shulou(Shulou.com)06/02 Report--

This article mainly shows you "how to use data objects NSNumber in ios". The content is simple and clear. I hope it can help you solve your doubts. Let me lead you to study and learn this article "how to use data objects NSNumber in ios".

1 Number Objects

Integers, floats, and longs are basic data types in object-c, not data objects.

Why do you need to use data objects: if you want to store data in NSArray, NSArray cannot store basic data types, so you need to put basic data types

Convert it to a data object and save it to NSArray. So that's what data objects are for.

1.1 create an integer data object

NSNumber * intNumber

NSInteger myInt

IntNumber = [NSNumber numberWithInteger: 100]

You can also use this initialization: intNumber = @ 100

/ / convert data objects to basic data types

MyInt = [intNumber integerValue]

NSLog (@ "% li", (long) myInt)

Note that the following access is incorrect:

NSLog (@ "% li", (long) [myNumber integerValue])

2 comparison of data objects

IsEqualToNumber: compare whether two data objects are equal

Compare: compare the size of 2 data objects

A compare:B

NSOrderedAscending: AB

3 the data object is immutable

NSNumber * myNumber = [[NSNumber alloc] initWithInt: 50]

...

[myNumber initWithInt: 1000]

Such code will make the program hang up, and the data object can only be initialized once.

4 numberWithInt: VS numberWithInteger:

Using the numberWithInt: method, you can only use intValue to restore its value to the base type, which can be printed using% I

Using the numberWithInteger: method, you can only use integerValue to restore its value to the basic type, and you can print its value with% li

5 the applications of api are as follows:

NumberWithChar: initWithChar: charValue

NumberWithUnsignedChar: initWithUnsignedChar: unsignedCharValue

NumberWithShort: initWithShort: shortValue

NumberWithUnsignedShort: initWithUnsignedShort: unsignedShortValue

NumberWithInteger: initWithInteger: integerValue

NumberWithUnsignedInteger: initWithUnsignedInteger: unsignedIntegerValue

NumberWithInt: initWithInt: intValue

NumberWithUnsignedInt: initWithUnsignedInt: unsignedIntValue

NumberWithLong: initWithLong: longValue

NumberWithUnsignedLong: initWithUnsignedLong: unsignedLongValue

NumberWithLongLong: initWithLongLong: longlongValue

NumberWithUnsignedLongLong: initWithUnsignedLongLong: unsignedLongLongValue

NumberWithFloat: initWithFloat: floatValue

NumberWithDouble: initWithDouble: doubleValue

NumberWithBool: initWithBool: boolValue

These are all the contents of the article "how to use data objects NSNumber in ios". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.