CODEWITHSUNDEEP
ios
user2480376
user2480376

Reputation: 13

Check if the values in an array go below a specific value

I have an array with double values that can range from 0.0 to 100.0. I would like to alert the user if any of the values are below 10.0. I did some searching and the closest thing I could find was:

- (BOOL)containsObject:(id)anObject

Is there any way I could use this method to see if the values are below 10? I tried the following line of code but received two errors. 

if ([myArray containsObject:[NSNumber numberWithDouble:(<10)])
{
    // Do something
}

I would appreciate the assistance. It seems like a pretty basic task.

Upvotes: 0

Views: 117

Answers (4)

JPetric
JPetric

Reputation: 3918

If it is not an array with lots of data, I don't see the reason why wouldn't you do it like this:

   for (NSNumber *number in myArray) {
        if ([number floatValue] < 10.0) {
            // alert user 
        }
    }

Upvotes: 5

Firo
Firo

Reputation: 15566

I would use blocks, they are cooler and it will help to familiarize yourself with them:

[myArray enumerateObjectsWithBlock^(NSNumber *number, NSUInteger indx, BOOL *stop) {
    if ([number floatValue] < 10.0) {
        // alert user

        // kill the loop to prevent unnecessarily going through all the elements
        stop = YES;
    }
}];

If you do want to user fast enumeration include a break:

for (NSNumber *number in myArray) {
     if ([number floatValue] < 10.0) 
           // alert user 
           break; // kills the loop
     }
 }

If you only care if one item is under 10 these approaches work well because you do not need to go through every element every time. Also, if this is the case, predicates are not efficient because they will filter the whole array when in reality you only care about one item (the first item under 10).

Upvotes: 0

iPatel
iPatel

Reputation: 47049

Use NSPredicate for more faster

NSPredicate *predicatePeople =  [NSPredicate predicateWithFormat:@"(startValue => %f) BETWEEN (endValue <= %f))",startNSNumber,endNSNumber];

NSArray *filteredArray = [myArray filteredArrayUsingPredicate:predicatePeople];
if(filteredArray.count > 0)
{
  UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Information" message:@"MyArray Contain between 1 to 10 value" delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
     [alert show];
}

Upvotes: 1

Davi Stuart
Davi Stuart

Reputation: 269

Also, the usage of containsObject: is for "equals" purpose, like [myArray containsObject:[NSNumber numberWithDouble:2.0]], not conditional like you did. So, the best is what JPetric mentioned.

for (NSNumber *number in myArray) {
        if ([number floatValue] < 10.0) {
            // alert user 
        }
    }

Upvotes: 0

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