1.如何把NSMutableArray 转化为NSString
//用字符将NSArray中的元素拼接起来
NSArray *array = [NSArray arrayWithObjects:@"hello",@"world",nil];
//如要用,:等字符串拼接，只需将下面的@" "空格换成@","或@":"即可
NSString *string = [array componentsJoinedByString:@" "];
NSLog(@"string = %@",string);
原文：http://www.cnblogs.com/HMJ-29/p/5210727.html