Make NSDictionary Monthwise from DateArray - ios

Question

I have an array of DateString , in which I have values of date,month and year .
Now I have sorted it in ascending order . Now I have to put it in to dictionary with this key-value pair :-
Key- "January" (Month Name) and Value:- array of dates in that month
can anyone suggest me how to do this ?

Answer 1

You write code, as everyone would do.
You need a dictionary that maps (year, month) to (array).
You start with an empty mutable dictionary. Then you loop through your items. For each item, get the year and month (I assume you don't want Januarys of different years together). Look up the year / month in the dictionary, getting the mutable array value. If it isn't there, add the (year, month) key with a new mutable array as the value. So now you have an array for the (year, month), and add the item to that array.
If your data is fixed at that point, you can iterate through the dictionary and replace all the mutable arrays with immutable arrays (just use copy). And instead of sorting all the items first, just sort the keys of the dictionary, so you are now sorted by month and year, then sort the arrays when you need them sorted. For example in a tableview, you only need those arrays sorted that are actually being displayed.

Answer 2

NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [[NSDateComponents alloc] init];
// Set your year and month here
[components setYear:2016];
NSMutableDictionary *dayAndMonthWiseList = [[NSMutableDictionary alloc] init];
for (int i=1; i<=12; i++)
{
[components setMonth:i];
NSDate *date = [calendar dateFromComponents:components];
NSRange range = [calendar rangeOfUnit:NSCalendarUnitDay inUnit:NSCalendarUnitMonth forDate:date];
NSMutableArray *dayList = [[[NSMutableArray alloc] init] mutableCopy];
for (int j=1; j<=range.length; j++)
{
[dayList addObject:[NSString stringWithFormat:#"%d",j]];
}
[dayAndMonthWiseList setObject:dayList forKey:[NSString stringWithFormat:#"%d",i]];
}
NSLog(#"Dic. :%#",dayAndMonthWiseList);
Result is :
Dic. :{
1 = (
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,
26,
27,
28,
29,
30,
31
);
10 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30,
31
);
11 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30
);
12 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30,
31
);
2 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29
);
3 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30,
31
);
4 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30
);
5 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30,
31
);
6 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30
);
7 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30,
31
);
8 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30,
31
);
9 = (
1,
2,
3,
4,
5,
6,
7,
8,
9,
10,
11,
12,
13,
14,
15,
16,
17,
18,
19,
20,
21,
22,
23,
24,
25,
26,
27,
28,
29,
30
);
}