如何編輯NSMutableArray數據？

Question

我有這樣的NSMutableArray

sections = [[NSMutableArray alloc] init]; 
[sections addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Electricity",@"Type",@"0",@"Count", nil]]; 
    [sections addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Water",@"Type",@"0",@"Count", nil]]; 
    [sections addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Mobile",@"Type",@"0",@"Count", nil]]; 
    [sections addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Internet",@"Type",@"0",@"Count", nil]]; 
    [sections addObject:[[NSMutableDictionary alloc] initWithObjectsAndKeys:@"Fixed Line",@"Type",@"0",@"Count", nil]]; 

，並讓說，用戶選擇從0更改爲水數爲10怎麼辦？

Answer 1

[[sections objectAtIndex:1] setObject:@"10" forKey:@"Count"];

一件事。當你用alloc + init創建對象時，你應該自己釋放它們。因此，對於每個NSMutableDictionary，您都有內存泄漏（在您的代碼中）。
使用[[[NSMutableDictionary alloc] initWithObjectsAndKeys:..., nil] autorelease];或[NSMutableDictionary dictionaryWithObjectsAndKeys:..., nil];（當然，以後可以製作類似for (NSMutableDictionary *dict in sections) [dict release];的東西，但這看起來很難看）。