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Django migration strategy for renaming a model and relationship fields
...n files (!).
Update: As ceasaro mentions, newer versions of Django are usually able to detect and ask if a model is renamed. So try manage.py makemigrations first and then check the migration file.
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How to succinctly write a formula with many variables from a data frame?
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There is a special identifier that one can use in a formula to mean all the variables, it is the . identifier.
y <- c(1,4,6)
d <- data.frame(y = y, x1 = c(4,-1,3), x2 = c(3,9,8), x3 = c(4,-4,-2))
mod <- lm(y ~ ., data = d)
You can also do things like this, to use all variables but...
How does C compute sin() and other math functions?
...on in C, contributed by IBM. Since October 2011, this is the code that actually runs when you call sin() on a typical x86-64 Linux system. It is apparently faster than the fsin assembly instruction. Source code: sysdeps/ieee754/dbl-64/s_sin.c, look for __sin (double x).
This code is very complex. N...
java.util.Date vs java.sql.Date
...ns, you've hit my favorite pet peeve with JDBC: Date class handling.
Basically databases usually support at least three forms of datetime fields which are date, time and timestamp. Each of these have a corresponding class in JDBC and each of them extend java.util.Date. Quick semantics of each of th...
How to use Boost in Visual Studio 2010
...te's answer is pretty good already, I'm going to expand on it more specifically for Visual Studio 2010 as requested, and include information on compiling in the various optional components which requires external libraries.
If you are using headers only libraries, then all you need to do is to unar...
Is there a limit to the length of a GET request? [duplicate]
...ns on request-target length are found in practice. It is RECOMMENDED that all HTTP senders and recipients support request-target lengths of 8000 or more octets." tools.ietf.org/html/…
– Mark Nottingham
Nov 16 '11 at 2:04
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Git alias with positional parameters
Basically I'm trying to alias:
7 Answers
7
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How is this fibonacci-function memoized?
...nacci definition, fib n = fib (n-1) + fib (n-2), the function itself gets called, twice from the top, causing the exponential explosion. But with that trick, we set out a list for the interim results, and go "through the list":
fib n = (xs!!(n-1)) + (xs!!(n-2)) where xs = 0:1:map fib [2..]
The tr...
Understanding the meaning of the term and the concept - RAII (Resource Acquisition is Initialization
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So why isn't that called "using the stack to trigger cleanup" (UTSTTC:)?
RAII is telling you what to do: Acquire your resource in a constructor! I would add: one resource, one constructor. UTSTTC is just one application of that, RAII is much ...
How does a hash table work?
... book knows the title of the book and the exact title to boot, then that's all it should take. With the title, the person, with the aid of the librarian, should be able to find the book easily and quickly.
So, how can you do that? Well, obviously you can keep some kind of list of where you put each...