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Ruby Arrays: select(), collect(), and map()
..., but a Hash. You can also use select here, but the block is given the key and value in this case:
irb(main):001:0> h = {:sku=>"507772-B21", :desc=>"HP 1TB 3G SATA 7.2K RPM LFF (3 .", :qty=>"", :qty2=>"1", :price=>"5,204.34 P"}
irb(main):002:0> h.select { |key, value| !value.em...
Can I pass parameters by reference in Java?
...itself which is passed by value, hence it appears to be pass-by-reference (and people often claim that it is). This is not the case, as shown by the following:
Object o = "Hello";
mutate(o)
System.out.println(o);
private void mutate(Object o) { o = "Goodbye"; } //NOT THE SAME o!
Will print Hello...
Message 'src refspec master does not match any' when pushing commits in Git
... Don't just follow this step blindly, look at what @Vi has mentioned, and then modify your push command to correct ref.
– Kumar
Jun 7 '12 at 16:43
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Typical .gitignore file for an Android app
Just put an Android project under git ( beanstalk ) version control via the command line ( mac terminal ). Next step is to set up exclusions.
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com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
...tions.
DB server has run out of connections.
Something in between Java and DB is blocking connections, e.g. a firewall or proxy.
To solve the one or the other, follow the following advices:
Verify and test them with ping.
Refresh DNS or use IP address in JDBC URL instead.
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How to avoid “RuntimeError: dictionary changed size during iteration” error?
...n you want to delete an object in inner dict. for example you have a dic A and dict B in dict A. if you want to delete object in dict B it occurs error
– Ali-T
Apr 18 at 6:35
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How persistent is localStorage?
...ttings are stored in it. Some settings require the user the write regex'es and they would be sad if their regex rules are gone at some point.
So now I am wondering just how persistent the localStorage is.
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How to conclude your merge of a file?
...d file (after you resolve conficts by yourself) should be added (git add), and if there is no unmerged file you should git commit
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Want to find records with no associated records in Rails
...drop the DISTINCT. Otherwise, I think you'd want to normalize out the data and index in that case. I might do that by creating a friend_ids hstore or serialized column. Then you could say Person.where(friend_ids: nil)
– Unixmonkey
Dec 20 '16 at 16:02
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Return multiple values to a method caller
I read the C++ version of this question but didn't really understand it.
27 Answers
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