#nsdictionary

YOLOKit

Giả sử bạn làm việc với một API có kết quả trả về như sau:

{ "created_at": "2013-05-25T03:39:05Z", "num_stars": 0, "num_replies": 0, "source": { "link": "http://riposteapp.net", "name": "Riposte", "client_id": "737a54nLCdLLutcs2VzhtNKGnnMrakc4" }, "text": "We need new rules for using acronyms. If googling an acronym does not find it in the first few links, you should spell it out instead.", "num_reposts": 0, "id": "6027821", "entities": { "mentions": [], "hashtags": [], "links": [] }, "html": "We need new rules for using acronyms. If googling an acronym does not find it in the first few links, you should spell it out instead.", "machine_only": false, "user": { "username": "jrinn", "avatar_image": { "url": "https://d2rfichhc2fb9n.cloudfront.net/image/5/eGiW2i1Ziwn9i1YyM5jE99Wwat97InMiOiJzMyIsImIiOiJhZG4tdXNlci1hc3NldHMiLCJrIjoiYXNzZXRzL3VzZXIvZGQvMDIvMzAvZGQwMjMwMDAwMDAwMDAwMC5qcGciLCJvIjoiIn0", "width": 200, "is_default": false, "height": 200 }, "description": { "text": "iPhone app developer and father.", "html": "iPhone app developer and father.", "entities": { "mentions": [], "hashtags": [], "links": [] } }, "locale": "en_US", "created_at": "2013-04-02T06:23:09Z", "canonical_url": "https://alpha.app.net/jrinn", "cover_image": { "url": "https://d2rfichhc2fb9n.cloudfront.net/image/5/kZ-JRmTbmd3WVPswTJ8Nwxzkf917InMiOiJzMyIsImIiOiJ0YXBwLWFzc2V0cyIsImsiOiJpL1UvaS9ZL1VpWW5xRFNvTUtyTEhLNXA0OHN2NkxmTmRVMC5qcGciLCJvIjoiIn0", "width": 960, "is_default": true, "height": 260 } } }

Bạn muốn lấy giá trị của avatar url, thông thường sẽ viết như sau:

NSString *url = [[[dictionary objectForKey:@"user"] objectForKey:@"avatar_image"] objectForKey:@"url"];

Nhìn code hơi dài, bạn có thể tận dụng NSKeyValueCoding protocol và viết ngắn gọn hơn như sau:

Fixed for each loop in objective c for accessing NSMutable dictionary #dev #it #asnwer

for each loop in objective c for accessing NSMutable dictionary

I am finding some difficulty in accessing mutable dictionary keys and values in Objective-C.

Suppose I have this:

NSMutableDictionary *xyz=[[NSMutableDictionary alloc] init];

I can set keys and values. Now, I just want to access each key and value, but I don’t know the number of keys set.

In PHP it is very easy, something as…

Fixed Difference between objectForKey and valueForKey? #dev #it #asnwer

Difference between objectForKey and valueForKey?

What is the difference between objectForKey and valueForKey? I looked both up in the documentation and they seemed the same to me.

Answer: Difference between objectForKey and valueForKey?

Here’s a great reason to use objectForKey: wherever possible instead of valueForKey: – valueForKey: with an unknown key will throw NSUnknownKeyExceptionsaying…

Fixed How to check if an NSDictionary or NSMutableDictionary contains a key? #dev #it #asnwer

How to check if an NSDictionary or NSMutableDictionary contains a key?

I need to check if an dict has a key or not. How?

Answer: How to check if an NSDictionary or NSMutableDictionary contains a key?

objectForKey will return nil if a key doesn’t exist.

Answer: How to check if an NSDictionary or NSMutableDictionary contains a key?

if ([mydict objectForKey:@"mykey"]) { // key exists. } else { //…

How to: Best practice? – Array/Dictionary as a Core Data Entity Attribute

Best practice? – Array/Dictionary as a Core Data Entity Attribute

I am new to Core Data. I have noticed that collection types are not available as attribute types and would like to know what the most efficient way is of storing array/dictionary type data as an attribute (e.g. the elements that make up an address like street, city, etc. does not require a separate entity and is more conveniently…

How to use NSJSONSerialization

I have a JSON string (from PHP’s json_encode() that looks like this:

[{"id": "1", "name":"Aaa"}, {"id": "2", "name":"Bbb"}]

I want to parse this into some sort of data structure for my iPhone app. I guess the best thing for me would be to have an array of dictionaries, so the 0th element in the array is a dictionary with keys "id" => "1" and "name" => "Aaa".

I do…