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Combine two ActiveRecord::Relation objects
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If you want to combine using AND (intersection), use merge:
first_name_relation.merge(last_name_relation)
If you want to combine using OR (union), use or†:
first_name_relation.or(last_name_relation)
† Only in ActiveRecord 5+; for 4.2 install ...
PostgreSQL naming conventions
...sitively when not quoted (it actually folds them to lowercase internally), and case sensitively when quoted; many people are not aware of this idiosyncrasy. Using always lowercase you are safe. Anyway, it's acceptable to use camelCase or PascalCase (or UPPER_CASE), as long as you are consistent: eit...
What reason is there to use null instead of undefined in JavaScript?
I've been writing JavaScript for quite a long time now, and I have never had a reason to use null . It seems that undefined is always preferable and serves the same purpose programmatically. What are some practical reasons to use null instead of undefined ?
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What is the difference between graph search and tree search?
What is the difference between graph search and tree search versions regarding DFS, A* searches in artificial intelligence ?
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Eclipse Workspaces: What for and why?
I have seen, read and thought of different ways of using workspaces (per project, per application (multi-asseted or not), per program language, per target (web-development, plugins,..), and so on) and I am still doubting what the best approach is.
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jQuery set checkbox checked
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Taking all of the proposed answers and applying them to my situation - trying to check or uncheck a checkbox based on a retrieved value of true (should check the box) or false (should not check the box) - I tried all of the above and found that using .prop("ch...
Releasing memory in Python
...llocator. The int type maintains a freelist with its own allocated memory, and clearing it requires calling PyInt_ClearFreeList(). This can be called indirectly by doing a full gc.collect.
Try it like this, and tell me what you get. Here's the link for psutil.Process.memory_info.
import os
import...
How to grep Git commit diffs or contents for a certain word?
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To illustrate the difference between -S<regex> --pickaxe-regex and -G<regex>, consider a commit with the following diff in the same file:
+ return !regexec(regexp, two->ptr, 1, &regmatch, 0);
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- hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
While git ...
Does Swift have documentation generation support?
...ocumentation in Quick Help (both in the popover when ⌥-clicking symbols, and in the Quick Help Inspector ⌥⌘2).
Symbol documentation comments are now based on the same Markdown syntax used by rich playground comments, so a lot of what you can do in playgrounds can now be used directly in sourc...
CSS: Control space between bullet and
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@Wolle Hmmm. It's an old comment, and I'm not sure of the concern -- If it's as to whether <SPAN> can utilize id or class tags, take a look at W3C. If the question is whether it can convey semantic meaning, see this answer. Technically, the <SPAN>...