如何防止NSMutableDictionary 或 NSMutableArray 为 nil ,导致数据无法写入~~

try:

NSMutableArray

*sectionTitles = [[NSMutableArrayalloc] init];[/code]or any of the following:

sectionTitles = [[NSMutableArrayalloc] initWithCapacity:sectionTitles.count];
sectionTitles = [NSMutableArraynew];
sectionTitles = [NSMutableArrayarray];
sectionTitles = [NSMutableArrayarrayWithCapacity:sectionTitles.count];

maybe some silly ones:

sectionTitles = [NSMutableArrayarrayWithArray:@[]];
sectionTitles = [@[] mutableCopy];