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Objective-C 可变字符串NSMutableString用法

NSMutableString不同于NSString,其值是可变的,因而对其操作时,不需要赋给其他对象来保存操作后的结果。

#import 

int main (int argc, const char * argv[])
{
    
    @autoreleasepool {
        NSMutableString * mstr=[NSMutableString stringWithString:@"This is a NSMutableString Object"];
        NSLog(@"%@",mstr);
        
        //插入字符
        [mstr insertString:@"前缀 " atIndex:0];
        NSLog(@"%@",mstr);
        [mstr appendString:@" 后缀"];
        NSLog(@"%@",mstr);
        [mstr deleteCharactersInRange:NSMakeRange(0, 3)];
        //删除字符,并非字节,这里是删除前缀
        NSLog(@"%@",mstr);
        
        NSRange subRange=[mstr rangeOfString:@" 后缀"];
        if(subRange.location!=NSNotFound){
            [mstr deleteCharactersInRange:subRange];
        }
        //先找出range,再删除,如果找不到,返回的range的location值为NSNotFound
        //替换子串 replaceCharactersInRange接收器 使用方法类似,因为是通过range,所以该方法只会替换一次
        NSLog(@"%@",mstr);
        [mstr replaceOccurrencesOfString:@"t" withString:@"T" options:nil range:NSMakeRange(0, [mstr length])];
        //把所有的t替换成T
         NSLog(@"%@",mstr);
        NSMutableString * str2=[NSMutableString alloc];
        str2=[str2 initWithContentsOfURL:([NSURL URLWithString:@"http://www.pocketdigi.com"]) encoding:(NSUTF8StringEncoding) error:nil];
        //下载HTML页面
        NSLog(@"%@",str2);
        
    }
    return 0;
    
}