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How do you delete an ActiveRecord object?
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Why it only updates deleted_at column data in my database? How can I delete the whole row of data?
– TommyQu
Sep 28 '17 at 15:42
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What's the opposite of 'make install', i.e. how do you uninstall a library in Linux?
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If sudo make uninstall is unavailable:
In a Debian based system, instead of (or after*) doing make install you can run sudo checkinstall to make a .deb file that gets automatically installed. You can then remove it using the system package manager (e.g. apt/synaptic/aptitude/...
calculating the difference in months between two dates
...if today is the 14th of March, then the two pervious months are calculated based on the fact that jan had 31 days in it, and feb hasd 29 days in it. now, youre correct in that my method is not the definition of a "general" month, & yours is! However, mine only applies if you are reporting things...
master branch and 'origin/master' have diverged, how to 'undiverge' branches'?
...work)
\
C master (your work)
You based commit C on commit A because that was the latest work you had fetched from upstream at the time.
However, before you tried to push back to origin, someone else pushed commit B.
Development history has diverged into sep...
Does Ruby have a string.startswith(“abc”) built in method?
... length of the given string—whereas index will have to search the entire base string. In a failure case, starts_with? will take one access (per string) and comparison, whereas index will walk almost the full length of the base string.
– OldPeculier
Jul 28 '14...
Why is the asterisk before the variable name, rather than after the type?
... @Kupiakos It only makes more sense until you learn C's declaration syntax based on "declarations follow use". Declarations use the exact same syntax that use of the same-typed variables do. When you declare an array of ints, it does not look like: int[10] x. This is simply not C's syntax. The gram...
How to write trycatch in R
... the code
urls <- c(
"http://stat.ethz.ch/R-manual/R-devel/library/base/html/connections.html",
"http://en.wikipedia.org/wiki/Xz",
"xxxxx"
)
readUrl <- function(url) {
out <- tryCatch(
{
# Just to highlight: if you want to use more than one
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UIView's frame, bounds, center, origin, when to use what?
...trol.
center - this is the property you will likely focus on for sprite based games and animations where movement or scaling may occur. By default animation and rotation will be based on the center of the UIView. It rarely makes sense to try and manage such objects by the frame property.
bound...
What is the difference between a map and a dictionary?
...e to query "is C present?".
The Computing Science notion of map though is based on the mathematical linguistic term mapping, which the Oxford Dictionary defines as:
mapping An operation that associates each element of a given set (the domain) with one or more elements of a second set (the range).
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Why does integer division in C# return an integer and not a float?
... result every time. One example off of the top of my head is changing the base of a number. Calculating each digit involves the integer division of a number along with the remainder, rather than the floating point division of the number.
Because of these (and other related) reasons, integer divis...