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Conditionally populate an array from another array - objectiveC

Answer 1

+1 A:

Comparisons of NSStrings to @"" using equality are effectively pointer comparisons. Thus, you can't just use someString != @"" to compare against the empty string. Instead, use isEqualToString: or test against a zero length.

Edit: Just for code readability, if you're using Objective C 2.0, you can replace your for loop and object retrieval by index with a foreach...

for (NSArray *logbookItem in logBookItems) {
  NSLog(NSLog(@"%@, %@, %@", [[logBookItem objectAtIndex:1] class], ...

Adam Wright 2010-10-01 11:55:36

Thanks, I had forgotten that. It's now much easier to read!

churchill614 2010-10-01 12:13:39

Answer 2

+1 A:

First change this :

([[logbookItems objectAtIndex: i] objectAtIndex: 1] != @"")

to :

(![[[logbookItems objectAtIndex: i] objectAtIndex: 1] isEqualToString:@""]

MathieuF 2010-10-01 11:57:43

Magic, I had forgotten that. I still have the problem with 0 numbers being copied into the array though. I must be doing something wrong, but I can't find what...

churchill614 2010-10-01 12:14:43

Actually I'd go for `([[[logbookItems objectAtIndex: i] objectAtIndex: 1] length] != 0)`

JeremyP 2010-10-01 14:05:23

Answer 3

+1 A:

Same goes for the NSNumber, you need to call intValue for example on it to compare against 0.

Eric Fortin 2010-10-01 12:19:17

Thanks, although if it is stored as an integer/float, as an NSNumber, why do I again need to get the integer/float value when making a comparison?

churchill614 2010-10-01 12:25:43

It still is an NSNumber so to retrieve that int/float you stored, you need to call intValue/floatValue.

Eric Fortin 2010-10-01 12:37:23

Gotcha, thanks. It's a shame you cant chose 2 answers to be correct, as both were for the different parts.

churchill614 2010-10-01 13:03:10

You can still upvote it though. ;)

Eric Fortin 2010-10-01 13:17:43

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Conditionally populate an array from another array - objectiveC

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