Object-C 开发学习笔记二：NSNumber和NSString

示例代码：

////  main.m//  test////  Created by Bin Shen on 12/28/14.//  Copyright (c) 2014 Bin Shen. All rights reserved.//#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) {    @autoreleasepool {                /* ---------- NSNumber ---------- */        // 创建NSNumber对象        NSNumber *monthNumber = [NSNumber numberWithInt:10];        NSNumber *lengthNumber = [[NSNumber alloc] initWithFloat:10.8];        NSLog(@"monthNumber : %@", monthNumber);        NSLog(@"lengthNumber : %@", lengthNumber);                // 还原成基本数据类型        int month = [monthNumber intValue];        float length = [lengthNumber floatValue];        NSLog(@"month : %d", month);        NSLog(@"length : %.1f", length);                /* ---------- NSString ---------- */        // 创建一个字符串常量        NSString *string1 = @"这是一个字符串常量";        NSLog(@"string1 : %@", string1);        // 创建一个空的字符串        NSString *string2 = [[NSString alloc] init];        NSString *string3 = [NSString string];        NSLog(@"string2 : %@", string2);        NSLog(@"string3 : %@", string3);        // 快速创建字符串        NSString *string4 = [[NSString alloc] initWithString:@"abc"];        NSString *string5 = [NSString stringWithString:@"xyz"];        NSLog(@"string4 : %@", string4);        NSLog(@"string5 : %@", string5);        // 创建一个格式化的字符串 堆区        NSString *string6 = [[NSString alloc] initWithFormat:@"整数: %d", 10];        NSString *string7 = [NSString stringWithFormat:@"浮点数: %f", 10.8];        NSLog(@"string6 : %@", string6);        NSLog(@"string7 : %@", string7);                // 字符串的比较        if([string4 isEqualToString:string5]) {            NSLog(@"same content");        } else {            NSLog(@"different content");        }                NSString *string8 = [NSString stringWithFormat:@"123"];        NSString *string9 = [NSString stringWithFormat:@"123"];        if([string8 isEqualToString: string9]) {            NSLog(@"same content");        } else {            NSLog(@"different content");        }                if(string8 == string9) {            NSLog(@"same pointer");        } else {            NSLog(@"different pointer");        }                //  比较字符串的大小        NSString *string10 = [[NSString alloc] initWithFormat:@"z"];        NSString *string11 = [[NSString alloc] initWithFormat:@"abcd"];        NSComparisonResult result = [string10 caseInsensitiveCompare:string11];        NSLog(@"result : %d", result);                // 求字符串的长度        NSLog(@"%d", [string11 length]);                // 字符串的转换        NSString *string12 = @"Hello World";        NSLog(@"upper : %@", [string12 uppercaseString]);        NSLog(@"lower : %@", [string12 lowercaseString]);        NSLog(@"upper : %@", [string12 capitalizedString]);                // 转换成基本数据类型        NSString *string13 = @"3.14";        float pi = [string13 floatValue];        NSLog(@"pi %.2f", pi);                // 字符串装换成数组        NSString *string14 = @"abc bcd xyz";        NSArray *array = [string14 componentsSeparatedByString:@" "];        NSLog(@"array : %@", array);        // 截取字符串        NSString *string15 = @"abcdefg";        NSString *subString1 = [string15 substringToIndex:2];        NSString *subString2 = [string15 substringFromIndex:2];        NSLog(@"subString1 : %@", subString1);        NSLog(@"subString2 : %@", subString2);        NSRange range = {4, 2};//        NSRange range;//        range.location = 4;//        range.length = 2;        NSString *subString3 = [string15 substringWithRange:range];        NSLog(@"subString3 : %@", subString3);                // 字符串的拼接        NSString *string16 = @"abc";        NSString *string17 = @"xyz";        NSString *appString1 = [[NSString alloc] initWithFormat:@"%@%@", string16, string17];        NSString *appString2 = [string16 stringByAppendingFormat:@"%@", string17];        NSString *appString3 = [string16 stringByAppendingString:string17];        NSLog(@"appString1 : %@", appString1);        NSLog(@"appString2 : %@", appString2);        NSLog(@"appString3 : %@", appString3);                // 查询字符串        NSString *link = @"abcdeftarget=_blankzyx";        NSRange range1 = [link rangeOfString:@"target=_blank"];        NSLog(@"%@", NSStringFromRange(range1));        if(range1.location != NSNotFound) {            NSLog(@"found");        }                //可变字符串        NSMutableString *mutableString1 = [[NSMutableString alloc] initWithFormat:@"abc"];        //插入        [mutableString1 insertString:@"...xyz" atIndex:3];        NSLog(@"mutableString1 : %@", mutableString1);        //替换        [mutableString1 replaceCharactersInRange:NSMakeRange(0, 3) withString:@"efg"];        NSLog(@"mutableString1 : %@", mutableString1);        //删除        [mutableString1 deleteCharactersInRange:NSMakeRange(0, 3)];        NSLog(@"mutableString1 : %@", mutableString1);    }    return 0;}