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Can someone explain collection_select to me in clear, simple terms?
...order(..) or something like that.
# In your example it is:
Author.all,
# then you should specify methods for generating options
:id, # this is name of method that will be called for every row, result will be set as key
:name_with_initial, # this is name of method that will be ...
How to declare global variables in Android?
...em you are encountering is how to save state across several Activities and all parts of your application. A static variable (for instance, a singleton) is a common Java way of achieving this. I have found however, that a more elegant way in Android is to associate your state with the Application con...
public friend swap member function
...truct vector
{
void swap(vector&) { /* swap members */ }
};
Naturally, then, our class should too, right? Well, not really. The standard library has all sorts of unnecessary things, and a member swap is one of them. Why? Let's go on.
What we should do is identify what's canonical, and w...
How to use '-prune' option of 'find' in sh?
... test (up to and including -prune) will return false for the stuff you actually want (ie: the stuff you don't want to prune out).
Here's an example:
find . -name .snapshot -prune -o -name '*.foo' -print
This will find the "*.foo" files that aren't under ".snapshot" directories. In this example, -na...
How to move a file?
...
os.rename(), shutil.move(), or os.replace()
All employ the same syntax:
import os
import shutil
os.rename("path/to/current/file.foo", "path/to/new/destination/for/file.foo")
shutil.move("path/to/current/file.foo", "path/to/new/destination/for/file.foo")
os.replace("p...
Group query results by month and year in postgresql
...he "date" attribute.
sum("Sales") as "Sales" : The SUM() function adds up all the "Sales" values, and supplies a case-sensitive alias, with the case sensitivity maintained by using double-quotes.
group by 1,2 : The GROUP BY function must contain all columns from the SELECT list that are not part o...
List of Delphi language features and version in which they were introduced/deprecated
...support in enable on Linux.
C++Builder and Delphi now use the same ABI for all calls.
Delphi 10.2 Tokyo
Support for Linux server apps (Intel 64-bit using LLVM and ARC).
Assigning a dynamic arrays to a pointer using the @ operator is only allowed when hard-casting the array.
More flexible name...
git revert back to certain commit [duplicate]
how do i revert all my files on my local copy back to a certain commit?
3 Answers
3
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Why both no-cache and no-store should be used in HTTP response?
...ce is still valid then the cache can respond with its representation, thus alleviating the need for the server to resend the entire resource.
no-store is effectively the full do not cache directive and is intended to prevent storage of the representation in any form of cache whatsoever.
I say what...
How do I compile and run a program in Java on my Mac?
...ional Java runtime and development environment out-of-the-box with OSX, so all you have to do is write a Java program and use the built-in tools to compile and run it.
Writing Your First Program
The first step is writing a simple Java program. Open up a text editor (the built-in TextEdit app works...