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Factors in R: more than an annoyance?
... data types in R is factors. In my experience factors are basically a pain and I never use them. I always convert to characters. I feel oddly like I'm missing something.
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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 ...
Get the index of the nth occurrence of a string?
...if you think about it. (IndexOf will return as soon as it finds the match, and you'll keep going from where it left off.)
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Python progression path - From apprentice to guru
I've been learning, working, and playing with Python for a year and a half now. As a biologist slowly making the turn to bio-informatics, this language has been at the very core of all the major contributions I have made in the lab. I more or less fell in love with the way Python permits me to expre...
Seedable JavaScript random number generator
The JavaScript Math.random() function returns a random value between 0 and 1, automatically seeded based on the current time (similar to Java I believe). However, I don't think there's any way to set you own seed for it.
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MySQL ON vs USING?
In a MySQL JOIN , what is the difference between ON and USING() ? As far as I can tell, USING() is just more convenient syntax, whereas ON allows a little more flexibility when the column names are not identical. However, that difference is so minor, you'd think they'd just do away with USI...
Why use the params keyword?
...ly doing to make the best choice.
– Allen Clark Copeland Jr
Nov 28 '15 at 22:15
2
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Append an object to a list in R in amortized constant time, O(1)?
...oldlist, list(someobj))
In general, R types can make it hard to have one and just one idiom for all types and uses.
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What does -1 mean in numpy reshape?
... (-1,3) but not (-1, -1)). It simply means that it is an unknown dimension and we want numpy to figure it out. And numpy will figure this by looking at the 'length of the array and remaining dimensions' and making sure it satisfies the above mentioned criteria
Now see the example.
z = np.array([[...
Pinging servers in Python
In Python, is there a way to ping a server through ICMP and return TRUE if the server responds, or FALSE if there is no response?
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