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explicit casting from super class to subclass
...signment Dog dog = (Dog) animal; does not generate a compilation error, but at runtime it generates a ClassCastException . Why can't the compiler detect this error?
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How to get the number of characters in a std::string?
How should I get the number of characters in a string in C++?
12 Answers
12
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Python: Tuples/dictionaries as keys, select, sort
Suppose I have quantities of fruits of different colors, e.g., 24 blue bananas, 12 green apples, 0 blue strawberries and so on.
I'd like to organize them in a data structure in Python that allows for easy selection and sorting. My idea was to put them into a dictionary with tuples as keys, e.g.,
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Why does datetime.datetime.utcnow() not contain timezone information?
...s this datetime not have any timezone info given that it is explicitly a UTC datetime ?
9 Answers
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Is it safe to assume a GUID will always be unique?
I know there is a minute possibility of a clash but if I generated a batch of 1000 GUIDs (for example), would it be safe to assume they're all unique to save testing each one?
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Oracle SQL Query for listing all Schemas in a DB
I wanted to delete some unused schemas on our oracle DB.
7 Answers
7
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notifyDataSetChanged example
I'm trying to use in my Android Application the notifyDataSetChanged() method for an ArrayAdapter but it doesn't work for me.
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Disable activity slide-in animation when launching new activity?
I have an activity which launches another activity, via a button click. By default, on newer OS versions of android, the OS will animate the new activity sliding in from right to left.
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What's the difference between session.Merge and session.SaveOrUpdate?
.../child objects or many-to-many relationships, I need to call either SaveOrUpdate or Merge . Usually, when I need to call SaveOrUpdate , the exception I get on calling Merge has to do with transient objects not being saved first.
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How to export all collections in MongoDB?
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For lazy people, use mongodump, it's faster:
mongodump -d <database_name> -o <directory_backup>
And to "restore/import" it (from directory_backup/dump/):
mongorestore -d <database_name> <directory_backup>
This wa...