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How to concatenate strings of a string field in a PostgreSQL 'group by' query?
...xt) (
SFUNC=string_agg_transfn,
STYPE=text
);
Custom variations (all Postgres versions)
Prior to 9.0, there was no built-in aggregate function to concatenate strings. The simplest custom implementation (suggested by Vajda Gabo in this mailing list post, among many others) is to use the bu...
Indexes of all occurrences of character in a string
...r Thank you very much for you answer, it seem to be right, but this is actually my first day with Java so I'm a little confused by the final result, this seems to output -1 at the end an I don't quite understand why! thanks!!
– Trufa
Feb 17 '11 at 20:55
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How to create a directory using Ansible
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If state=directory, all immediate subdirectories will be created if they do not exist, since 1.7 they will be created with the supplied permissions.
– Alex
Oct 6 '16 at 10:05
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Learning Regular Expressions [closed]
I don't really understand regular expressions. Can you explain them to me in an easy-to-follow manner? If there are any online tools or books, could you also link to them?
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Dependency Injection vs Factory Pattern
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When using a factory your code is still actually responsible for creating objects. By DI you outsource that responsibility to another class or a framework, which is separate from your code.
sha...
XPath: How to select nodes which have no attributes?
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//node[not(@*)]
That's the XPath to select all nodes named "node" in the document without any attributes.
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The tilde operator in C
...F hashing algorithm, and I'm curious what it does. (The code is from Eternally Confused .)
6 Answers
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How do I delete NuGet packages that are not referenced by any project in my solution?
...h the new version. They each have only a Manage button -- but no uninstall button. And when you look to see where they are used, you can see that they are referenced by none of the solution's projects? They are NOT displaying an Uninstall?
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How to shrink the .git folder
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you should not delete all changes older than 30 days (i think it's somehow possible exploiting git, but really not recommended).
you can call git gc --aggressive --prune, which will perform garbage collection in your repository and prune old obje...
Default constructor vs. inline field initialization
...ference.
However, if you do have explicit constructors, I'd prefer to put all initialization code into those (and chain them) rather than splitting it up between constructors and field initializers.
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