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How do you delete an ActiveRecord object?
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It's destroy and destroy_all methods, like
user.destroy
User.find(15).destroy
User.destroy(15)
User.where(age: 20).destroy_all
User.destroy_all(age: 20)
Alternatively you can use delete and delete_all which won't enforce :before_destro...
scp or sftp copy multiple files with single command
...te server in different directories.
For example, I want to run these 4 commands at once.
15 Answers
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Can we write our own iterator in Java?
If I have a list containing [alice, bob, abigail, charlie] and I want to write an iterator such that it iterates over elements that begin with 'a', can I write my own ? How can I do that ?
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Unable to begin a distributed transaction
...sing supported cloning tools such as SYSPREP.
Running 'msdtc -uninstall' and then 'msdtc -install' from the command
prompt will fix the problem. Note: Running 'msdtc -uninstall' will
result in the system losing all MS DTC configuration information.
For more information, see Help and Suppo...
Reset push notification settings for app
...mentation. The current solution seems to be resetting the device's content and settings.
Update: The tech note has been updated with new steps that work correctly as of iOS 7.
Delete your app from the device.
Turn the device off completely and turn it back on.
Go to Settings > General...
What is the difference between class and instance methods?
What's the difference between a class method and an instance method?
18 Answers
18
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Why is transposing a matrix of 512x512 much slower than transposing a matrix of 513x513?
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The explanation comes from Agner Fog in Optimizing software in C++ and it reduces to how data is accessed and stored in the cache.
For terms and detailed info, see the wiki entry on caching, I'm gonna narrow it down here.
A cache is organized in sets and lines. At a time, only one set is u...
How to check if variable is string with python 2 and 3 compatibility
... str) work as expected in python-2.x? Or will I need to check the version and use isinstance(x, basestr) ?
10 Answers
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How does delete[] know it's an array?
...eed the delete[] syntax at all? Why can't a single delete form be used to handle all deletes?
The answer to this goes back to C++'s roots as a C-compatible language (which it no longer really strives to be.) Stroustrup's philosophy was that the programmer should not have to pay for any features tha...
How do I do a not equal in Django queryset filtering?
In Django model QuerySets, I see that there is a __gt and __lt for comparitive values, but is there a __ne / != / <> ( not equals ?)
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