CODEWITHSUNDEEP
iosobjective-c
RGriffiths
RGriffiths

Reputation: 5970

Interrogating an NSArray that appears to have a null entry

I have an iPad app that links to an SQL database to retrieve information in the following way:

NSString *strGetCodeUrl = [NSString stringWithFormat:@"%@", @"http://website/getdevicecode.php?device=" , deviceName];
NSArray *deviceArray = [[NSMutableArray alloc] initWithContentsOfURL:[NSURL URLWithString:strGetCodeUrl]];

This works when there is a device that matches and it retrieves the required information. However if there is not a match it returns

("")

The array however appears to have one record. Ideally I would like to stop this from happening and for the array to be empty if there is no match. Alternatively (although not very tidy) I could check the length of the entry at index 0 but I am struggling with this method. 

NSString *deviceCode = [deviceArray objectAtIndex:0];
if ( [deviceCode length] == 0)
{
device does not exist
}

Any advice gratefully received.

Upvotes: 0

Views: 55

Answers (2)

cjwirth
cjwirth

Reputation: 2013

I don't think you can tell the init method to leave out empty strings...

However, you can do this:

NSString *strGetCodeUrl = [NSString stringWithFormat:@"%@", @"http://website/getdevicecode.php?device=" , deviceName];
NSArray *deviceArray = [[NSMutableArray alloc] initWithContentsOfURL:[NSURL URLWithString:strGetCodeUrl]];
[deviceArray removeObject:@""];

Which also isn't as tidy as perhaps you were hoping for, but it will remove all empty strings. But at least its just 1 line of code as opposed to about 3 for the if

Per the documentation:

Removes all occurrences in the array of a given object.

Upvotes: 1

Antonio MG
Antonio MG

Reputation: 20410

What about this:

NSString *deviceCode = [deviceArray objectAtIndex:0];
if ([deviceCode isEqualToString:@""])
{
device does not exist
}

Upvotes: 2

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