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Difference between Destroy and Delete
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Basically destroy runs any callbacks on the model while delete doesn't.
From the Rails API:
ActiveRecord::Persistence.delete
Deletes the record in the database and freezes this instance to reflect that no changes should be ...
List goals/targets in GNU make that contain variables in their definition
...utput from make -pn (i.e. make --print-data-base --dry-run)? It prints out all the variables, rules, implicit rules and which commands will be run in laborious detail.
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What use is find_package() if you need to specify CMAKE_MODULE_PATH anyway?
...e. Now the software has a few dependencies. I compiled them myself and installed them on my system.
4 Answers
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Disable messages upon loading a package
...y R script is being used for further analysis I want to completely disable all of this output. How do I do that? Furthermore, I'd prefer to do it without having to modify ROCR at all, so that future users of this script don't have to do that either.
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Is “double hashing” a password less secure than just hashing it once?
...o compute a hash for each password and see if it matches the stored hash.
All passwords are not equally likely. Attackers might exhaustively search all short passwords, but they know that their chances for brute-force success drop sharply with each additional character. Instead, they use an ordered...
How to find list of possible words from a letter matrix [Boggle Solver]
Lately I have been playing a game on my iPhone called Scramble. Some of you may know this game as Boggle. Essentially, when the game starts you get a matrix of letters like so:
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Check if table exists and if it doesn't exist, create it in SQL Server 2008
...read, and you don't have to worry about sys.objects vs. sysobjects vs. sys.all_objects
vs. sys.tables. Basic form:
IF object_id('MyTable') is not null
PRINT 'Present!'
ELSE
PRINT 'Not accounted for'
Of course this will show as "Present" if there is any object present with that name. If yo...
What is the strict aliasing rule?
...n(void)
{
// Get a 32-bit buffer from the system
uint32_t* buff = malloc(sizeof(Msg));
// Alias that buffer through message
Msg* msg = (Msg*)(buff);
// Send a bunch of messages
for (int i = 0; i < 10; ++i)
{
msg->a = i;
msg->b = i+1;...
Named colors in matplotlib
... have been moved under the 'xkcd:' prefix since I posted this answer originally.
I really didn't change much from the matplotlib example, but here is the code for completeness.
import matplotlib.pyplot as plt
from matplotlib import colors as mcolors
colors = dict(mcolors.BASE_COLORS, **mcolors...
What is the JavaScript equivalent of var_dump or print_r in PHP? [duplicate]
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This really is not a proper answer as this is not an inherent feature or function of JavaScript and there are innumerable scenarios where one will absolutely not have access to console.log()
– Chris Rasys
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