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Argparse optional positional arguments?
I have a script which is meant to be used like this:
usage: installer.py dir [-h] [-v]
3 Answers
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Why use double indirection? or Why use pointers to pointers?
...ol;
//fill data structure
word = malloc(4 * sizeof *word); // assume it worked
strcpy(word, "foo");
sentence = malloc(4 * sizeof *sentence); // assume it worked
sentence[0] = word;
sentence[1] = word;
sentence[2] = word;
sentence[3] = NULL;
monologue = malloc(4...
For i = 0, why is (i += i++) equal to 0?
...ppens is more involved than that - take a look at MSDN, 7.5.9 Postfix increment and decrement operators:
The run-time processing of a postfix increment or decrement operation of the form x++ or x-- consists of the following steps:
If x is classified as a variable:
x is evaluated ...
How to create a temporary directory?
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Use mktemp -d. It creates a temporary directory with a random name and makes sure that file doesn't already exist. You need to remember to delete the directory after using it though.
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What does “atomic” mean in programming?
...es the first 32 bits, and a second one which writes the last 32 bits. That means that another thread might read the value of foo, and see the intermediate state.
Making the operation atomic consists in using synchronization mechanisms in order to make sure that the operation is seen, from any othe...
HashMap get/put complexity
...ashMap get/put operations are O(1). However it depends on the hash implementation. The default object hash is actually the internal address in the JVM heap. Are we sure it is good enough to claim that the get/put are O(1) ?
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How can I create a correlation matrix in R?
I have 92 set of data of same type.
5 Answers
5
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Getting the count of unique values in a column in bash
...t count first). How would I accomplish this in a Linux command line environment?
5 Answers
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How to use the CancellationToken property?
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You can implement your work method as follows:
private static void Work(CancellationToken cancelToken)
{
while (true)
{
if(cancelToken.IsCancellationRequested)
{
return;
}
Console.Write...
“INSERT IGNORE” vs “INSERT … ON DUPLICATE KEY UPDATE”
While executing an INSERT statement with many rows, I want to skip duplicate entries that would otherwise cause failure. After some research, my options appear to be the use of either:
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