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The model used to open the store is incompatible with the one used to create the store

...el select your new version of data model for current data model THAT'S NOT ALL ) You should perform so called "light migration". Go to your AppDelegate and find where the persistentStoreCoordinator is being created Find this line if (![_persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteS...
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In which situations do we need to write the __autoreleasing ownership qualifier under ARC?

...ents that are passed by reference (id *) and are autoreleased on return. All of this is very well explained in the ARC transition guide. In your NSError example, the declaration means __strong, implicitly: NSError * e = nil; Will be transformed to: NSError * __strong error = nil; When you c...
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How do you calculate the average of a set of circular data? [closed]

... sum_i_from_1_to_N cos(a[i]) The method given by starblue is computationally equivalent, but his reasons are clearer and probably programmatically more efficient, and also work well in the zero case, so kudos to him. The subject is now explored in more detail on Wikipedia, and with other uses, l...
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Leaflet - How to find existing markers, and delete markers?

... Should be a way to collect all of the layers used by Leaflet. :/ – jackyalcine Aug 1 '12 at 21:39 10 ...
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How to pass a user defined argument in scrapy spider

... The above code is only partially working for me. For eg. If I define domain using self.domain, I'm still not able to access it outside the __init__ method. Python throws a not defined error. BTW, why have you omitted the super call? PS. I'm working wit...
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Counting inversions in an array

...m to do the following: Given array A[1... n] , for every i < j , find all inversion pairs such that A[i] > A[j] . I'm using merge sort and copying array A to array B and then comparing the two arrays, but I'm having a difficult time seeing how I can use this to find the number of inversions...
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std::enable_if to conditionally compile a member function

... I want to use std::enable_if to choose between two member-functions and allow only one of them to be used. 7 Answers ...
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Django: How do I add arbitrary html attributes to input fields on a form?

... earlier to modify 3 fields: ``` for field_name in ['image', 'image_small', 'image_mobile']: field = self.fields.get(field_name) field.widget.attrs['data-file'] = 'file' ``` – Stuart Axon Jun 6 '14 at 11:59 ...
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How can I force users to access my page over HTTPS instead of HTTP?

... The way I've done it before is basically like what you wrote, but doesn't have any hardcoded values: if($_SERVER["HTTPS"] != "on") { header("Location: https://" . $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"]); exit(); } ...
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Can you do a partial checkout with Subversion?

...ight find useful. From the documentation: ... sparse directories (or shallow checkouts) ... allows you to easily check out a working copy—or a portion of a working copy—more shallowly than full recursion, with the freedom to bring in previously ignored files and subdirectories at a later tim...