集合的递归深拷贝
关于拷贝的一些概念在iOS集合的深复制与浅复制里 讲得很清楚啦.
我在这里想说的是递归深拷贝:
copy只做第一级的深拷贝。 如果array里面存的是指针，它就会把指针值做深拷贝，等于是后面的数组跟前面的数组，存的指针值是一样的，但是指针指向的内容不做深拷贝，所以改了指针指向的内容，会同时影响两个数组。
如果需要每一层都深拷贝的话:
NSMutableArray* a = [NSMutableArray arrayWithObjects:@"123",@"345", nil];
NSMutableArray* b = [NSMutableArray arrayWithObjects:@"xyz",@"abc", nil];
NSArray *c = [NSArray arrayWithObjects:a, b, nil];
NSArray *d = [c copyDeeply]; // 深拷贝
for (NSArray* arr in d) {
for (NSString* s in arr) {
NSLog(@"element: %@", s);
}
}
a[0] = @"haha";
for (NSArray* arr in d) {
for (NSString* s in arr) {
NSLog(@"element: %@", s);
}
}
结果:
2017-04-05 11:26:23.688 Test[1341:101216] element: 123
2017-04-05 11:26:23.688 Test[1341:101216] element: 345
2017-04-05 11:26:23.688 Test[1341:101216] element: xyz
2017-04-05 11:26:23.688 Test[1341:101216] element: abc
2017-04-05 11:26:23.689 Test[1341:101216] element: 123
2017-04-05 11:26:23.689 Test[1341:101216] element: 345
2017-04-05 11:26:23.689 Test[1341:101216] element: xyz
2017-04-05 11:26:23.689 Test[1341:101216] element: abc
******************************************
NSArray 递归深拷贝
- (id)copyDeeply {
NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:[self count]];
[self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
id item = obj;
if ([item respondsToSelector:@selector(copyDeeply)]) {
item = [item copyDeeply];
} else {
item = [item copy];
}
if (item) {
[array addObject:item];
}
}];
return [NSArray arrayWithArray:array];
}
- (id)mutableCopyDeeply {
NSMutableArray *array = [[NSMutableArray alloc] initWithCapacity:[self count]];
[self enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
id item = obj;
if ([item respondsToSelector:@selector(mutableCopyDeeply)]) {
item = [item mutableCopyDeeply];
} else if ([item respondsToSelector:@selector(mutableCopyWithZone:)]) {
item = [item mutableCopy];
} else {
item = [item copy];
}
if (item) {
[array addObject:item];
}
}];
return array;
}
NSDictionary 递归深拷贝
- (id)copyDeeply {
NSMutableDictionary *dic = [[NSMutableDictionary alloc] initWithCapacity:[self count]];
[self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
id item = obj;
if ([item respondsToSelector:@selector(copyDeeply)]) {
item = [item copyDeeply];
} else {
item = [item copy];
}
if ( item && key ) {
[dic setObject:item forKey:key];
}
}];
return [NSDictionary dictionaryWithDictionary:dic];
}
- (id)mutableCopyDeeply {
NSMutableDictionary *dic = [[NSMutableDictionary alloc] initWithCapacity:[self count]];
[self enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
id item = obj;
if ([item respondsToSelector:@selector(mutableCopyDeeply)]) {
item = [item mutableCopyDeeply];
} else if ([item respondsToSelector:@selector(mutableCopyWithZone:)]) {
item = [item mutableCopy];
} else {
item = [item copy];
}
if ( item && key ) {
[dic setObject:item forKey:key];
}
}];
return dic;
}