`NSArray`&#39;s `arrayByAddingObjectsFromArray:` is more-or-less equivalent to JavaScript&#39;s `.concat()` method:

    NSArray *newArray=[firstArray arrayByAddingObjectsFromArray:secondArray];

Note: If `firstArray` is nil, `newArray` will be nil. This can be fixed by using the following:

    NSArray *newArray=firstArray?[firstArray arrayByAddingObjectsFromArray:secondArray]:[[NSArray alloc] initWithArray:secondArray];

If you want to strip-out duplicates:

    NSArray *uniqueEntries = (NSArray *)[[NSSet setWithArray:newArray] allObjects];

Here&#39;s a symmetric &amp; simple way by just beginning with an empty array:

    NSArray* newArray = @[];
    newArray = [newArray arrayByAddingObjectsFromArray:firstArray];
    newArray = [newArray arrayByAddingObjectsFromArray:secondArray];

Having something like

 - created_by 
 - created_date 
 - modified_by
 - modified_date

Would be a very common pattern for a lot of tables.

1) You can set created date automatically (but not others) in model.py with

    created_date = models.DateTimeField(auto_now_add=True, editable=False)

2) You could do created/modified dates (but not by/user as don&#39;t have request context) in model.py with

    def save(self):
        if self.id:
            self.modified_date = datetime.now()
        else:
            self.created_date = datetime.now()
        super(MyModel,self).save()

3) You could set the created/modifed date and by in admin.py - but this doesn&#39;t deal with non admin updates

    def save_model(self, request, obj, form, change):
        if change:
            obj.modified_by = request.user
            obj.modified_date = datetime.now()
        else:
            obj.created_by = request.user
            obj.created_date = datetime.now()
        obj.save()

4) And the final place would be in the view.py which can do all 4, but doesn&#39;t cover admin updates.

So realistically have to have logic spread out, at a minimum repeated in 3 &amp; 4 (or a method on the model called from both, which will be missed)

Whats a better way?  (I&#39;ve been working with python/django for a couple of days so could easily be missing something obvious)

  - Can you do someting like @login_required e.g. @audit_changes
  - Can you get access to the request and current user in the model and centralise logic there?

DRY way to add created/modified by and time

I&#39;m starting to explore Scala, and one of the things I&#39;m intrigued by is the `Option` type and the promise of being able to eliminate `null` related errors.

However I haven&#39;t been able to work out how to transform a list (or other collection) of, say, `Option[String]`, to a collection of `String` (obviously filtering out any values that are `None`).

In other words, how do I get from this:

    List[Option[Int]] = List(Some(1))

... to this:

    List[Int] = List(1)

I&#39;m using Scala 2.8 if that has any impact on the answer.

How to transform Scala collection of Option[X] to collection of X

What is the Objective-C equivalent of the JavaScript `concat()` function?

Assuming that both objects are arrays, how would you combine them?

How would I combine two arrays in Objective-C?

<p>What is the Objective-C equivalent of the JavaScript <code>concat()</code> function?</p>
<p>Assuming that both objects are arrays, how would you combine them?</p>


I set up my application to either send debugging output to console or a log file. Now, I&#39;d like to decide with in the code whether 


- it is run in the debugger (or simulator) and have thus a console window where I would like to read the output directly or if 
- there is no console window and thus, the output should be redirected to a file.

Is there a way to determine if the app runs in the debugger?

Detecting if iOS app is run in debugger

    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapTapTap:)];
    [self.view1 addGestureRecognizer:tapGesture];
    [self.view2 addGestureRecognizer:tapGesture];
    [tapGesture release];

In the above code only taps on `view2` are recognized. If I comment out the third line then taps on `view1` are recognized. If I&#39;m right and you can only use a gesture recognizer once, I&#39;m not sure if this is a bug or it just needs some more documentation.

Can you attach a UIGestureRecognizer to multiple views?

I am using &lt;a href=&quot;http://log.scifihifi.com/post/55837387/simple-iphone-keychain-code&quot;&gt;idandersen&#39;s scifihifi-iphone&lt;/a&gt; code for keychain and save password using

    [SFHFKeychainUtils storeUsername:@&quot;User&quot; andPassword:@&quot;123&quot;
                  forServiceName:@&quot;TestService&quot; updateExisting:YES error:&amp;error];

When I delete the application from the device, the password remains in the keychain.

I want to remove the password from the keychain when the user deletes the application from the device. How can I do this?


Delete keychain items when an app is uninstalled

What is the maximum size of an iOS application? any constraints?

Max size of an iOS application

I’ve been working on an application for a couple of years and received a simple design request: Round the corners on a UIView and add a drop shadow.To do as given below.

I want a custom `UIView`... : I just wanted a blank white view with rounded corners and a light drop shadow (with no lighting effect). I can do each of those one by one but the usual `clipToBounds`/`maskToBounds` conflicts occur.

[![enter image description here][1]][1]


  [1]: https://i.stack.imgur.com/zp17N.png

UIView with rounded corners and drop shadow?

In iPhone App,
while running the App on device How to detect the screen resolution of the device on which App is running?

in iPhone App How to detect the screen resolution of the device

So I found the question about how to view the change history of a file, but the change history of this particular file is huge and I&#39;m really only interested in the changes of a particular method. So would it be possible to see the change history for just that particular method?

I know this would require git to analyze the code and that the analysis would be different for different languages, but method/function declarations look very similar in most languages, so I thought maybe someone has implemented this feature.

The language I&#39;m currently working with is Objective-C and the SCM I&#39;m currently using is git, but I would be interested to know if this feature exists for any SCM/language.

Content Type	Original Author	Original Content on Stackoverflow
Question	Moshe	View Question on Stackoverflow
Solution 1 - Ios	grahamparks	View Answer on Stackoverflow
Solution 2 - Ios	meaning-matters	View Answer on Stackoverflow

How would I combine two arrays in Objective-C?

Ios Problem Overview

Ios Solutions

Solution 1 - Ios

Solution 2 - Ios

How to transform Scala collection of Option[X] to collection of X

DRY way to add created/modified by and time

Attributions