How to get key/value pair from NSDictionary?

问题

I need little help with NSDictionary. How can I get 1 pair, lets say a value for "id" if I have dictionary

NSDictionary *allCourses = [NSJSONSerialization JSONObjectWithData:allCoursesData options:NSJSONReadingMutableContainers error:&error];

and it looks like this:

Thanks for Your help.

回答1:

The shortest way:

NSNumber *number = allCourses[@"semacko"][@"id"];

回答2:

Try this:

NSDictionary *allCourses = [NSJSONSerialization JSONObjectWithData:allCoursesData options:NSJSONReadingMutableContainers error:&error];
        [allCourses enumerateKeysAndObjectsUsingBlock: ^(id key, id obj, BOOL *stop) {
    // do something with key and obj
}];

回答3:

NSDictionary *semacko = [allCourses objectForKey:@"semacko"];
NSNumber *number = [semacko objectForKey:@"id"];

回答4:

NSNumber *number = allCourses[@"semacko"][@"id"];

or if you want to iterate all objects:

for(NSDictionary* course in allCourses) {
    NSNumber *number = course[@"id"];
}

回答5:

NSString *name =[[NSString alloc]initWithFormat:@"%@",[Dictionaryname objectForKey:@"key"]];

by this code you can access the value that corresponds to the key that specified in the objectforkey keyword

回答6:

You can try:

NSNumber *courseID = [allCourses valueForKeyPath:@"semacko.id"];

For setting value:

- setValue:forKeyPath:

来源：https://stackoverflow.com/questions/21824528/how-to-get-key-value-pair-from-nsdictionary