我有一个JSON供稿：
{
"count1" = 2;
"count2" = 2;
idval = 40;
level = "<null>";
"logo_url" = "/assets/logos/default_logo_medium.png";
name = "Golf Club";
"role_in_club" = Admin;
}
问题是"<null>"我无法弄清楚如何从NSDictionary中保存到之前NSUserDefaults的去除。
请帮我解决这个问题。 谢谢！
翻翻字典，迭代和寻找任何空条目并删除它们。
NSMutableDictionary *prunedDictionary = [NSMutableDictionary dictionary];
for (NSString * key in [yourDictionary allKeys])
{
if (![[yourDictionary objectForKey:key] isKindOfClass:[NSNull class]])
[prunedDictionary setObject:[yourDictionary objectForKey:key] forKey:key];
}
在此之后， prunedDictionary应该在原来的字典中的所有非空项。
另一个变化，没有（明确）循环：
NSMutableDictionary *dict = [yourDictionary mutableCopy];
NSArray *keysForNullValues = [dict allKeysForObject:[NSNull null]];
[dict removeObjectsForKeys:keysForNullValues];
使用这个从词典中删除空
- (NSMutableDictionary *)recursive:(NSMutableDictionary *)dictionary {
for (NSString *key in [dictionary allKeys]) {
id nullString = [dictionary objectForKey:key];
if ([nullString isKindOfClass:[NSDictionary class]]) {
[self recursive:(NSMutableDictionary*)nullString];
} else {
if ((NSString*)nullString == (id)[NSNull null])
[dictionary setValue:@"" forKey:key];
}
}
return dictionary;
}
下面是含有字典和阵列哪些值也可以是词典和辞典阵列我的基于类别的递归溶液：
文件的NSDictionary + Dario.m：
#import "NSArray+Dario.h"
@implementation NSDictionary (Dario)
- (NSDictionary *) dictionaryByReplacingNullsWithEmptyStrings {
const NSMutableDictionary *replaced = [NSMutableDictionary new];
const id nul = [NSNull null];
const NSString *blank = @"";
for(NSString *key in self) {
const id object = [self objectForKey:key];
if(object == nul) {
[replaced setObject:blank forKey:key];
} else if ([object isKindOfClass:[NSDictionary class]]) {
[replaced setObject:[object dictionaryByReplacingNullsWithEmptyStrings] forKey:key];
} else if ([object isKindOfClass:[NSArray class]]) {
[replaced setObject:[object arrayByReplacingNullsWithEmptyStrings] forKey:key];
} else {
[replaced setObject:object forKey:key];
}
}
return [NSDictionary dictionaryWithDictionary:(NSDictionary*)replaced];
}
@end
文件的NSArray + Dario.m：
#import "NSDictionary+Dario.h"
@implementation NSArray (Dario)
- (NSArray *) arrayByReplacingNullsWithEmptyStrings {
const NSMutableArray *replaced = [NSMutableArray new];
const id nul = [NSNull null];
const NSString *blank = @"";
for (int i=0; i<[self count]; i++) {
const id object = [self objectAtIndex:i];
if ([object isKindOfClass:[NSDictionary class]]) {
[replaced setObject:[object dictionaryByReplacingNullsWithEmptyStrings] atIndexedSubscript:i];
} else if ([object isKindOfClass:[NSArray class]]) {
[replaced setObject:[object arrayByReplacingNullsWithEmptyStrings] atIndexedSubscript:i];
} else if (object == nul){
[replaced setObject:blank atIndexedSubscript:i];
} else {
[replaced setObject:object atIndexedSubscript:i];
}
}
return [NSArray arrayWithArray:(NSArray*)replaced];
}
要删除它，把它转换成一个可变的字典和删除对象的关键“级别”;
NSDictionary* dict = ....; // this is the dictionary to modify
NSMutableDictionary* mutableDict = [dict mutableCopy];
[mutableDict removeObjectForKey:@"level"];
dict = [mutableDict copy];
如果你不使用ARC，你需要添加到“释放”几个电话。
更新：
如果你不知道密钥（S）与名"<null>"对象，那么你必须遍历：
NSDictionary* dict = ....; // this is the dictionary to modify
NSMutableDictionary* mutableDict = [dict mutableCopy];
for (id key in dict) {
id value = [dict objectForKey: key];
if ([@"<null>" isEqual: value]) {
[mutableDict removeObjectForKey:key];
}
}
dict = [mutableDict copy];
要找到"<null>"的价值观，我使用的，因为字符串比较"<null>"是你的样品中的字符串。 但我不知道这是否真的是这样。
我相信这是最节约资源的方式
//上的NSDictionary类实现
- (NSDictionary *)dictionaryByRemovingNullValues {
NSMutableDictionary * d;
for (NSString * key in self) {
if (self[key] == [NSNull null]) {
if (d == nil) {
d = [NSMutableDictionary dictionaryWithDictionary:self];
}
[d removeObjectForKey:key];
}
}
if (d == nil) {
return self;
}
return d;
}
我已经创建了NSJSOn序列化类的类别。
创建类和进口类中使用它的方法...
// Mutable containers are required to remove nulls.
if (replacingNulls)
{
// Force add NSJSONReadingMutableContainers since the null removal depends on it.
opt = opt || NSJSONReadingMutableContainers;
}
id JSONObject = [self JSONObjectWithData:data options:opt error:error];
if ((error && *error) || !replacingNulls)
{
return JSONObject;
}
[JSONObject recursivelyReplaceNullsIgnoringArrays:ignoreArrays withString:replaceString];
return JSONObject;
我想你的问题的解决和我得到它
NSDictionary *dict = [[NSDictionary alloc]initWithObjectsAndKeys:@"2",@"count1",@"2",@"count2",@"40",@"idval",@"<null>",@"level",@"/assets/logos/default_logo_medium.png",@"logo_url",@"Golf Club",@"name",@"role_in_club",@"Admin", nil];
NSMutableDictionary *mutableDict = [dict mutableCopy];
for (NSString *key in [dict allKeys]) {
if ([dict[key] isEqual:[NSNull null]]) {
mutableDict[key] = @"";
}
if([dict[key] isEqualToString:@"<null>"])
{
mutableDict[key] = @"";
}
}
dict = [mutableDict copy];
NSLog(@"The dict is - %@",dict);
最后的答案是
The dict is - {
Admin = "role_in_club";
count1 = 2;
count2 = 2;
idval = 40;
level = "";
"logo_url" = "/assets/logos/default_logo_medium.png";
name = "Golf Club";
}
我做这样。
NSMutableDictionary *prunedDict = [NSMutableDictionary dictionary];
[self enumerateKeysAndObjectsUsingBlock:^(NSString *key, id obj, BOOL *stop) {
if (![obj isKindOfClass:[NSNull class]]) {
prunedDict[key] = obj;
}
}];
下面的代码是确定当结果是数组或字典，您可以通过编辑更改代码将结果返回给零或空字符串
功能是递归的，所以可以在字典解析阵列。
-(id)changeNull:(id)sender{
id newObj;
if ([sender isKindOfClass:[NSArray class]]){
NSMutableArray *newArray = [[NSMutableArray alloc] init];
for (id item in sender){
[newArray addObject:[self changeNull:item]];
}
newObj = newArray;
}
else if ([sender isKindOfClass:[NSDictionary class]]){
NSMutableDictionary *newDict = [[NSMutableDictionary alloc] init];
for (NSString *key in sender){
NSDictionary *oldDict = (NSDictionary*)sender;
id item = oldDict[key];
if (![item isKindOfClass:[NSDictionary class]] && ![item isKindOfClass:[NSArray class]]){
if ([item isEqual:[NSNull null]]){
item = @"";
}
[newDict setValue:item forKey:key];
}
else{
[newDict setValue:[self changeNull:item] forKey:key];
}
}
newObj = newDict;
}
return newObj;
}
jsonresult（{描述= “”; ID = 1;名称=高;}，{描述= “”; ID = 2;名称=中;}，{描述= “”; ID = 3;名称=低;}）
改变空（{描述= “”; ID = 1;名称=高;}，{描述= “”; ID = 2;名称=中;}，{描述= “”; ID = 3;名称=低;} ）
Swift 3.0/4.0解决方案
以下是该解决方案，当JSON有sub-dictionaries 。 这将大大-通过所有的dictionaries ，分-dictionaries的JSON和删除NULL(NSNull) key-value从对JSON 。
extension Dictionary {
func removeNull() -> Dictionary {
let mainDict = NSMutableDictionary.init(dictionary: self)
for _dict in mainDict {
if _dict.value is NSNull {
mainDict.removeObject(forKey: _dict.key)
}
if _dict.value is NSDictionary {
let test1 = (_dict.value as! NSDictionary).filter({ $0.value is NSNull }).map({ $0 })
let mutableDict = NSMutableDictionary.init(dictionary: _dict.value as! NSDictionary)
for test in test1 {
mutableDict.removeObject(forKey: test.key)
}
mainDict.removeObject(forKey: _dict.key)
mainDict.setValue(mutableDict, forKey: _dict.key as? String ?? "")
}
if _dict.value is NSArray {
let mutableArray = NSMutableArray.init(object: _dict.value)
for (index,element) in mutableArray.enumerated() where element is NSDictionary {
let test1 = (element as! NSDictionary).filter({ $0.value is NSNull }).map({ $0 })
let mutableDict = NSMutableDictionary.init(dictionary: element as! NSDictionary)
for test in test1 {
mutableDict.removeObject(forKey: test.key)
}
mutableArray.replaceObject(at: index, with: mutableDict)
}
mainDict.removeObject(forKey: _dict.key)
mainDict.setValue(mutableArray, forKey: _dict.key as? String ?? "")
}
}
return mainDict as! Dictionary<Key, Value>
}
}
收藏此3种方法在您的视图控制器，并调用此方法像这样
NSDictionary *dictSLoginData = [self removeNull:[result valueForKey:@"data"]];
- (NSDictionary*)removeNull:(NSDictionary *)dict {
NSMutableDictionary *replaced = [NSMutableDictionary dictionaryWithDictionary: dict];
const id nul = [NSNull null];
const NSString *blank = @"";
for (NSString *key in [dict allKeys]) {
const id object = [dict objectForKey: key];
if (object == nul) {
[replaced setObject: blank forKey: key];
} else if([object isKindOfClass: [NSDictionary class]]) {
[replaced setObject: [self replaceNull:object] forKey: key];
} else if([object isKindOfClass: [NSArray class]]) {
[replaced setObject: [self replaceNullArray:object] forKey: key];
}
}
return [NSDictionary dictionaryWithDictionary: replaced];
}
- (NSArray *)replaceNullArray:(NSArray *)array {
const id nul = [NSNull null];
const NSString *blank = @"";
NSMutableArray *replaced = [NSMutableArray arrayWithArray:array];
for (int i=0; i < [array count]; i++) {
const id object = [array objectAtIndex:i];
if (object == nul) {
[replaced replaceObjectAtIndex:i withObject:blank];
} else if([object isKindOfClass: [NSDictionary class]]) {
[replaced replaceObjectAtIndex:i withObject:[self replaceNull:object]];
} else if([object isKindOfClass: [NSArray class]]) {
[replaced replaceObjectAtIndex:i withObject:[self replaceNullArray:object]];
}
}
return replaced;
}
- (NSDictionary *)replaceNull:(NSDictionary *)dict {
const id nul = [NSNull null];
const NSString *blank = @"";
NSMutableDictionary *replaced = [NSMutableDictionary dictionaryWithDictionary: dict];
for (NSString *key in [dict allKeys]) {
const id object = [dict objectForKey: key];
if (object == nul) {
[replaced setObject: blank forKey: key];
} else if ([object isKindOfClass: [NSDictionary class]]) {
[replaced setObject: [self replaceNull:object] forKey: key];
} else if([object isKindOfClass: [NSArray class]]) {
[replaced setObject: [self replaceNullArray:object] forKey: key];
}
}
return replaced;
}
