NSString

一、根据字符串的宽度计算字符串的高度

-(CGSize)sizeWithFont:(UIFont *)font maxSize:(CGSize)maxSize string:(NSString *)string{
    
    NSDictionary *attrs = @{NSFontAttributeName:font};
        
    return [string boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;
    
}

二、字符串截取、匹配、分隔

//1.截取字符串
    
NSString *string =@"123456d890";
NSString *str1 = [string substringToIndex:5];//截取掉下标5之前的字符串
NSLog(@"截取的值为：%@",str1);
 NSString *str2 = [string substringFromIndex:3];//截取掉下标3之后的字符串
NSLog(@"截取的值为：%@",str2);

//2.匹配字符串
NSString *string =@"sd是sfsfsAdfsdf";
NSRange range = [string rangeOfString:@"Ad"];//匹配得到的下标
NSLog(@"rang:%@",NSStringFromRange(range));
string = [string substringWithRange:range];//截取范围内的字符串
NSLog(@"截取的值为：%@",string);

//3.分隔字符串
NSString *string =@"sdfsfsfsAdfsdf";
    
NSArray *array = [string componentsSeparatedByString:@"A"]; //从字符A中分隔成2个元素的数组
NSLog(@"array:%@",array); //结果是adfsfsfs和dfsdf

三、字符串替换

NSString *strUrl = [urlString stringByReplacingOccurrencesOfString:@" " withString:@""];  去掉空格

NSString *strUrl = [urlString stringByReplacingOccurrencesOfString:@" " withString:@"/"];替换字符