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How to use WeakReference in Java and Android development?
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231
Using a WeakReference in Android isn't any different than using one in plain old Java. Here is...
Default value of function parameter
... suppose:
lib.h
int Add(int a, int b);
lib.cpp
int Add(int a, int b = 3) {
...
}
test.cpp
#include "lib.h"
int main() {
Add(4);
}
The compilation of test.cpp will not see the default parameter declaration, and will fail with an error.
For this reason, the default parameter definit...
rotating axis labels in R
...f axis labels. (0=parallel, 1=all horizontal, 2=all perpendicular to axis, 3=all vertical)
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switch() statement usage
...e) {
switch(type,
mean = 1,
median = 2,
trimmed = 3)
}
test2 <- function(type) {
if (type == "mean") 1
else if (type == "median") 2
else if (type == "trimmed") 3
}
system.time( for(i in 1:1e6) test1('mean') ) # 0.89 secs
system.time( for(i in 1:1e6) test2('mean') ) #...
Turning multi-line string into single comma-separated
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93
You can use awk and sed:
awk -vORS=, '{ print $2 }' file.txt | sed 's/,$/\n/'
Or if you want ...
Find column whose name contains a specific string
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239
Just iterate over DataFrame.columns, now this is an example in which you will end up with a lis...
How do I open links in Visual Studio in my web browser and not in Visual Studio?
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63
There is an extension that provides this behavior called Open in External Browser. It works in V...
How to remove all CSS classes using jQuery/JavaScript?
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13 Answers
13
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How to synchronize a static variable among threads running different instances of a class in Java?
...nchronized (countLock) {
count++;
}
}
}
Method 3 is the best in many cases because the lock object is not exposed outside of your class.
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