第八章、数字、字符串和集合

//8_1
#import <Foundation/NSAutoreleasePool.h> #import <Foundation/NSValue.h> #import <Foundation/NSString.h> int main (intargc, char *argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePoolalloc] init]; NSNumber*myNumber, *floatNumber, *intNumber; NSIntegermyInt; //NSInerger是64位或者32位整形的typedef // integer value intNumber = [NSNumbernumberWithInteger: 100]; myInt = [intNumberintegerValue]; NSLog (@"%li", (long) myInt); //100 // long value myNumber = [NSNumbernumberWithLong: 0xabcdef]; NSLog (@"%lx", [myNumberlongValue]); //abcdef // char value myNumber = [NSNumbernumberWithChar: 'X']; NSLog (@"%c", [myNumbercharValue]); //X
NSString
• 用于创建和处理字符串对象的类 • 由Unichar组成，可以处理包含百万字符 的字符集，使其能够在全世界不同语言环 境下使用
C char Objective-C Unichar
unichar字符占用16位，而Unicode标准提供的大小大于16位。因此，将来，unichar字符可能大于 16位，底线是绝对不要对Unicode字符的大小作任何假定
NSNumber(cont.)
// float value floatNumber = [NSNumbernumberWithFloat: 100.00]; NSLog (@"%g", [floatNumberfloatValue]); //100 // double myNumber = [NSNumbernumberWithDouble: 12345e+15]; NSLog (@"%lg", [myNumberdoubleValue]); //1.2345e+19 // Wrong access here NSLog (@"%i", [myNumberintegerValue]); //0 // Test two Numbers for equality if ([intNumberisEqualToNumber: floatNumber] == YES) NSLog (@"Numbers are equal"); //yes else NSLog(@"Numbers are not equal"); // Test if one Number is <, ==, or > second Number if ([intNumbercompare: myNumber] == NSOrderedAscending) NSLog (@"First number is less than second"); //yes [pool drain]; return 0; }
// Extract chars to end of string starting at index 6 res = [str1 substringFromIndex: 5]; //is string A NSLog (@"Chars from index 5 of str1: %@", res); // Extract chars from index 8 through 13 (6 chars) res = [[str1 substringFromIndex: 8] substringToIndex: 6]; //string NSLog (@"Chars from index 8 through 13: %@", res); // An easier way to do the same thing res = [str1 substringWithRange: NSMakeRange (8, 6)]; //string NSLog (@"Chars from index 8 through 13: %@", res); // Locate one string inside another subRange = [str1 rangeOfString: @"string A"]; NSLog (@"String is at index %lu, length is %lu", subRange.location, subRange.length); //8 8 subRange = [str1 rangeOfString: @"string B"]; if (subRange.location == NSNotFound) NSLog (@"String not found"); //YES else NSLog (@"String is at index %lu, length is %lu", subRange.location, subRange.length); [pool drain]; return 0; }
// Copy one string to the end of another str2 = [str1 stringByAppendingString: str2]; //This is stringAThis is string B NSLog (@"Concatentation: %@", str2); // Test if 2 strings are equal if ([str1 isEqualToString: res] == YES) //YES NSLog (@"str1 == res"); else NSLog (@"str1 != res"); // Test if one string is <, == or > than another compareResult = [str1 compare: str2]; if (compareResult == NSOrderedAscending) NSLog (@"str1 < str2"); //YES else if (compareResult == NSOrderedSame) NSLog (@"str1 == str2"); else // NSOrderedDescending NSLog (@"str1 > str2"); // Convert a string to uppercase res = [str1 uppercaseString]; NSLog (@"Uppercase conversion: %s", [res UTF8String]); // Convert a string to lowercase res = [str1 lowercaseString]; NSLog (@"Lowercase conversion: %@", res); NSLog (@"Original string: %@", str1); [pool drain]; return 0; }
NSNumber(cont.)
3、integerValue:等检索实例方法不会检 查所提取的数据类型是否符合方法要求 4、compare:比较两个NSNumber对象 NSOrderedAscending; NSOrderedDescending; NSOrderSame;
内容概要
Foundation简介 NSNumber NSString NSArray NSDictionary NSSet
ቤተ መጻሕፍቲ ባይዱ
NSString(cont.)
//demo 8_3 // Basic String Operations – Continued #import <Foundation/NSObject.h> #import <Foundation/NSString.h> #import <Foundation/NSAutoreleasePool.h> int main (intargc, char *argv[]) { NSAutoreleasePool *pool = [[NSAutoreleasePoolalloc] init]; NSString *str1 = @"This is string A"; NSString *str2 = @"This is string B"; NSString *res; NSRangesubRange; //用于指定范围，定义在 //<Foundation/NSRange.h>(<Foundation/NSString.h>中已经包含这个头文件)， //实际上它是结构体的typedef，包含两个分量location和length // Extract first 4 chars from string res = [str1 substringToIndex: 3]; //Thi NSLog (@"First 3 chars of str1: %@", res);