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Can I make the foreign key field optional in Django model
...'').
– fang_dejavu
Jun 20 '16 at 18:32
8
@Ward, both are not needed. It is sufficient to just use...
How do I run a Node.js application as its own process?
.../bin
Environment=NODE_ENV=production
WorkingDirectory=/var/www/myapp
[Install]
WantedBy=multi-user.target
Note if you're new to Unix: /var/www/myapp/app.js should have #!/usr/bin/env node on the very first line.
Copy your service file into the /etc/systemd/system folder.
Tell systemd about the ...
What does `void 0` mean? [duplicate]
...rns undefined.
Examples
void 0
void (0)
void "hello"
void (new Date())
//all will return undefined
What's the point of that?
It seems pretty useless, doesn't it? If it always returns undefined, what's wrong with just using undefined itself?
In a perfect world we would be able to safely just us...
What is JAXB and why would I use it? [closed]
...
I'm a big fan of JAXB for manipulating XML. Basically, it provides a solution to this problem (I'm assuming familiarity with XML, Java data structures, and XML Schemas):
Working with XML is difficult. One needs a way to take an XML file - which is basically a text file - a...
Binary Data in JSON String. Something better than Base64
...builtin functions, but the space efficiency is bad -- a 105% expansion (if all input bytes are equally likely) vs. 25% for base85 or 33% for base64.
Final verdict: base64 wins, in my opinion, on the grounds that it's common, easy, and not bad enough to warrant replacement.
See also: Base91 and Bas...
Rails: Check output of path helper from console
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troutwine
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answered May 17 '10 at 2:01
ChubasChubas
1...
Equivalent of “continue” in Ruby
...
Ian PurtonIan Purton
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14
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int to hex string
...
To print an int32 it should just use "X8", not "X4". If you want X4, you should indeed make sure to use an Int16.
– Nyerguds
Oct 10 '16 at 8:49
...
Speed up the loop operation in R
...Biggest problem and root of ineffectiveness is indexing data.frame, I mean all this lines where you use temp[,].
Try to avoid this as much as possible. I took your function, change indexing and here version_A
dayloop2_A <- function(temp){
res <- numeric(nrow(temp))
for (i in 1:nrow(te...
LINQ Single vs First
...should NOT use one, when you mean the other.
Note: In my code, I will typically use FirstOrDefault() and SingleOrDefault() but that's a different question.
Take, for example, a table that stores Customers in different languages using a Composite Key ( ID, Lang ):
DBContext db = new DBContext();
Cust...