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How to set JAVA_HOME in Linux for all users
...
For all users, I would recommend placing the following line in /etc/profile
export JAVA_HOME=$(readlink -f /usr/bin/javac | sed "s:/bin/javac::")
This will update dynamically and works well with the alternatives system. Do not...
printf with std::string?
...f what it expects definitely won't give you the results you want. It's actually undefined behaviour, so anything at all could happen.
The easiest way to fix this, since you're using C++, is printing it normally with std::cout, since std::string supports that through operator overloading:
std::cout...
Is it possible to ping a server from Javascript?
...ther parts of the source but you get the idea).
function Pinger_ping(ip, callback) {
if(!this.inUse) {
this.inUse = true;
this.callback = callback
this.ip = ip;
var _that = this;
this.img = new Image();
this.img.onload = function() {_that.good();};
this.img.onerro...
What are the Dangers of Method Swizzling in Objective-C?
...
I think this is a really great question, and it's a shame that rather than tackling the real question, most answers have skirted the issue and simply said not to use swizzling.
Using method sizzling is like using sharp knives in the kitchen. So...
Algorithm for creating a school timetable
...ere are known solutions for algorithm of creating a school timetable. Basically, it's about optimizing "hour-dispersion" (both in teachers and classes case) for given class-subject-teacher associations. We can assume that we have sets of classes, lesson subjects and teachers associated with each ot...
What does -> mean in Python function definitions?
...
And the information is available as a .__annotations__ attribute.
– Martijn Pieters♦
Jan 17 '13 at 13:06
9
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Python dictionary: Get list of values for list of keys
...n list-comp:
Build list and throw exception if key not found: map(mydict.__getitem__, mykeys)
Build list with None if key not found: map(mydict.get, mykeys)
Alternatively, using operator.itemgetter can return a tuple:
from operator import itemgetter
myvalues = itemgetter(*mykeys)(mydict)
# use ...
Is it possible to implement a Python for range loop without an iterator variable?
...ou can just live with the extra i variable.
Here is the option to use the _ variable, which in reality, is just another variable.
for _ in range(n):
do_something()
Note that _ is assigned the last result that returned in an interactive python session:
>>> 1+2
3
>>> _
3
F...
Oracle TNS names not showing when adding new connection to SQL Developer
...cognized, use the following procedure:
Define an environmental variable called TNS_ADMIN to point to the folder that contains your tnsnames.ora file.
In Windows, this is done by navigating to Control Panel > System > Advanced system settings > Environment Variables...
In Linux, define...
What is the difference between user and kernel modes in operating systems?
... CPU instruction and
reference any memory address. Kernel
mode is generally reserved for the
lowest-level, most trusted functions
of the operating system. Crashes in
kernel mode are catastrophic; they
will halt the entire PC.
User Mode
In User mode, the executing code has no abili...