NSString *tempA = @"123";
 NSString *tempB = @"456";

 NSString *newString = [NSString stringWithFormat:@"%@%@",tempA,tempB];

int intString = [newString intValue];

NSString *stringInt = [NSString stringWithFormat:@"%d",intString];

 float floatString = [newString floatValue];

NSString *stringFloat = [NSString stringWithFormat:@"%f",intString];

NSString*string =@"sdfsfsfsAdfsdf";
string = [string substringToIndex:7];//截取下标7之后的字符串
NSLog(@"截取的值为：%@",string);
[string substringFromIndex:2];//截取下标2之前的字符串
NSLog(@"截取的值为：%@",string);

NSString*string =@"sdfsfsfsAdfsdf";
NSRangerange = [stringrangeOfString:@"f"];//匹配得到的下标
NSLog(@"rang:%@",NSStringFromRange(range));
string = [string substringWithRange:range];//截取范围类的字符串
NSLog(@"截取的值为：%@",string);

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