How to update NSMutableDictionary?

Question

I have an NSMutableDictionary.

NSMutableDictionary* plistDict = [[NSMutableDictionary alloc] initWithContentsOfFile:path];

I have to update an element in that dictionary. How i can do that?

i have to remove an object and insert another value for a key.This NSMutableDictionary is a plist of application settings of user. User will change it frequently. — S.P., Feb 09 '10 at 07:22

score 12 · Accepted Answer · answered Feb 09 '10 at 07:19

12

Please refer to the API here

First retrieve the objects using

[dict objectForKey:@"key"];

Later, you can set them back using:

- (void)setObject:(id)anObject forKey:(id)aKey
- (void)setValue:(id)value forKey:(NSString *)key

answered Feb 09 '10 at 07:19

Mihir Mathuria

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thanks. i tried like this. it worked.. [plistDict removeObjectForKey:@"name"] ; [plistDict setObject:@"my name" forKey:@"name"]; – S.P. Feb 09 '10 at 07:34
1

You don't need to remove the object for a key before setting the new value. – rpetrich Feb 09 '10 at 08:35
i need only [plistDict setObject:@"my name" forKey:@"name"]; ? ok. i will try this .Thanks. – S.P. Feb 09 '10 at 08:48

score 2 · Answer 2 · answered Nov 09 '12 at 14:31

2

dictionary only allows you to have one objects for each key so if you use "set object for key" it will update the current one

answered Nov 09 '12 at 14:31

pedrotorres

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score 2 · Answer 3 · edited Apr 17 '18 at 14:03

2

NSMutableDictionary's method addEntriesFromDictionary.

https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSMutableDictionary_Class/Reference/Reference.html

If both dictionaries contain the same key, the receiving dictionary’s previous value object for that key is sent a release message, and the new value object takes its place.

edited Apr 17 '18 at 14:03

MRizwan33

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answered Jan 26 '13 at 14:45

Renetik

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How to update NSMutableDictionary?

3 Answers3