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Is double square brackets [[ ]] preferable over single square brackets [ ] in Bash?
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[[ has fewer surprises and is generally safer to use. But it is not portable - POSIX doesn't specify what it does and only some shells support it (beside bash, I heard ksh supports it too). For example, you can do
[[ -e $b ]]
to test whether a ...
C/C++ maximum stack size of program
...nment variable in the OS. You can then check the stack size with ulimit -s and set it to a new value with for example ulimit -s 16384.
Here's a link with default stack sizes for gcc.
DFS without recursion:
std::stack<Node> dfs;
dfs.push(start);
do {
Node top = dfs.top();
if (top is ...
Reshape three column data frame to matrix (“long” to “wide” format) [duplicate]
...y ways to do this. This answer starts with what is quickly becoming the standard method, but also includes older methods and various other methods from answers to similar questions scattered around this site.
tmp <- data.frame(x=gl(2,3, labels=letters[24:25]),
y=gl(3,1,6, labe...
Ember.js or Backbone.js for Restful backend [closed]
... will keep the application open for long periods of time, perhaps all day, and interactions with the application's views or underlying data trigger deep changes in the view hierarchy. Ember is larger than Backbone, but thanks to Expires, Cache-Control this only matters on the the first load. After t...
Cosmic Rays: what is the probability they will affect a program?
Once again I was in a design review, and encountered the claim that the probability of a particular scenario was "less than the risk of cosmic rays" affecting the program, and it occurred to me that I didn't have the faintest idea what that probability is.
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Best way of invoking getter by reflection
...will always have a getter method. I know that I can use setAccesible(true) and get its value (when there is no PermissionManager), though I prefer to invoke its getter method.
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Why does GCC generate such radically different assembly for nearly the same C code?
...I've managed to see how GCC optimizes the first case.
Before we can understand why they are so different, first we must understand how GCC optimizes fast_trunc_one().
Believe it or not, fast_trunc_one() is being optimized to this:
int fast_trunc_one(int i) {
int mantissa, exponent;
mantissa...
Can PHP cURL retrieve response headers AND body in a single request?
Is there any way to get both headers and body for a cURL request using PHP? I found that this option:
13 Answers
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Jackson serialization: ignore empty values (or null)
I'm currently using jackson 2.1.4 and I'm having some trouble ignoring fields when I'm converting an object to a JSON string.
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RSpec: What is the difference between a feature and a request spec?
What is the conceptual difference between Rspec's feature specs and request specs ?
1 Answer
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