Sorting one array in the same order as another array

Question

I have two arrays. Let's say:

array = "Dave", "Mike", "Joe", "Jason", "Kevin"

and

IQ = 110, 145, 75, 122, 130

I want to sort them by IQ. Say Highest to lowest. I can sort one array... and then I go back and check to see what position it was in and then rearrange the other array. It seems like there must be a better way to do this. Especially if the array gets larger.

Here is how I'm doing it right now.

d1, d2, d3, d4, d5 are my IQ variable. I use the sortBack array to rearrange another array in the same order.

NSMutableArray *myArray = [NSMutableArray arrayWithObjects:[NSString stringWithFormat:@"%d",d1], [NSString stringWithFormat:@"%d",d2],[NSString stringWithFormat:@"%d",d3], [NSString stringWithFormat:@"%d",d4],[NSString stringWithFormat:@"%d",d5], nil];

//sorting
[myArray sortUsingComparator:^NSComparisonResult(NSString *str1, NSString *str2) {
    return [str1 compare:str2 options:(NSNumericSearch)];
}];

for(int i=0;i<5;i++)
{
    if([[myArray objectAtIndex:i] integerValue]==d1)
    {
        sortBackArray[i]=1;
    }
    else if([[myArray objectAtIndex:i] integerValue]==d2)
    {
        sortBackArray[i]=2;
    }
    else if([[myArray objectAtIndex:i] integerValue]==d3)
    {
        sortBackArray[i]=3;
    }
    else if([[myArray objectAtIndex:i] integerValue]==d4)
    {
        sortBackArray[i]=4;
    }
    else if([[myArray objectAtIndex:i] integerValue]==d5)
    {
        sortBackArray[i]=5;
    }
}

Why are you maintaining two arrays for this. It's better to have an array of dictionaries with name and IQ values. You can then create a sortDescriptor with key IQ and sort the array. When you have a related info, always keep them together. — Anupdas
– Anupdas, Commented May 23, 2013 at 9:31
Yea, I thought that might be the way to go, but I tend to get confused with the dictionary stuff. I'll take a look at it again. — Cherr Skees
– Cherr Skees, Commented May 23, 2013 at 9:35
It would be very difficult if you are not making use of dictionaries or custom model objects to keep data structured. I have posted an example. Take a look. — Anupdas
– Anupdas, Commented May 23, 2013 at 9:42

Anupdas · Accepted Answer · 2013-05-23 09:41:58Z

19

This would be a better way to make a dictionary for users. And then sorting based on their specific values like IQ, Name etc.

NSArray *users = @[@"Dave",@"Mike",@"Joe",@"Jason",@"Kevin"];
NSArray *iqs = @[@110,@145,@75,@122,@130];

NSMutableArray *array = [NSMutableArray array];
for (int idx = 0;idx<[users count];idx++) {
    NSDictionary *dict = @{@"Name": users[idx],@"IQ":iqs[idx]};
    [array addObject:dict];
}

NSSortDescriptor *descriptor = [NSSortDescriptor sortDescriptorWithKey:@"IQ" ascending:NO];
[array sortUsingDescriptors:@[descriptor]];

answered May 23, 2013 at 9:41

Anupdas

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1 Comment

Pravin Kamble Over a year ago

Actually i want this type of sort based on date....Thanks for saving my time ....it works like magic!!!!

alecxe · Accepted Answer · 2013-05-23 10:16:11Z

3

Construct a 2d array with first row as names and second row as IQ Sort this array according to the IQ in O(nlogn)

edited May 23, 2013 at 10:16

alecxe

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answered May 23, 2013 at 9:58

Aditya

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