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MySQL Conditional Insert
... WHERE user = 123
AND item = 456)
In this, dual is a table with one row only (found originally in Oracle, now in mysql too). The logic is that the SELECT statement generates a single row of data with the required values, but only when the v...
Specify sudo password for Ansible
...
You can pass variable on the command line via --extra-vars "name=value". Sudo password variable is ansible_sudo_pass. So your command would look like:
ansible-playbook playbook.yml -i inventory.ini --user=username \
--extra-var...
What does “not run” mean in R help pages?
...isible on help pages, but will
be run both by the package checking tools, and the
'example()' function. This was previously 'testonly', and
that form is still accepted.
share
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improve this ans...
Why do pthreads’ condition variable functions require a mutex?
...adcast to, one or more of the threads on the waiting list will be woken up and the mutex will be magically locked again for that thread.
You typically see the following operation with condition variables, illustrating how they work. The following example is a worker thread which is given work via a...
What is the difference between NaN and None?
I am reading two columns of a csv file using pandas readcsv() and then assigning the values to a dictionary. The columns contain strings of numbers and letters. Occasionally there are cases where a cell is empty. In my opinion, the value read to that dictionary entry should be None but instead ...
JavaScript string encryption and decryption?
I'm interested in building a small app for personal use that will encrypt and decrypt information on the client side using JavaScript. The encrypted information will be stored in a database on a server, but never the decrypted version.
...
Multiple inheritance/prototypes in JavaScript
... false,
}));
}
Explanation
A proxy object consists of a target object and some traps, which define custom behavior for fundamental operations.
When creating an object which inherits from another one, we use Object.create(obj). But in this case we want multiple inheritance, so instead of obj I ...
How to change Navigation Bar color in iOS 7?
... you set the translucent property to NO.
Availability
Available in iOS 7.0 and later.
Declared In
UINavigationBar.h
Code
NSArray *ver = [[UIDevice currentDevice].systemVersion componentsSeparatedByString:@"."];
if ([[ver objectAtIndex:0] intValue] >= 7) {
// iOS 7.0 or later
self.navig...
Cache busting via params
... a system for doing so. My thought was to apply a param to the end of css and js files with the current version number:
12...
what is Promotional and Feature graphic in Android Market/Play Store?
What does it mean and need whether we are uploading our app into the market? Please Explain or give me a related links.
7 A...