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How are multi-dimensional arrays formatted in memory?
...things are going to happen. Here's a quick example:
int array1[3][2] = {{0, 1}, {2, 3}, {4, 5}};
In memory looks like this:
0 1 2 3 4 5
exactly the same as:
int array2[6] = { 0, 1, 2, 3, 4, 5 };
But if you try to pass array1 to this function:
void function1(int **a);
you'll get a warnin...
What is the difference between 127.0.0.1 and localhost
... still have to do an actual lookup of localhost somewhere.
If you use 127.0.0.1, then (intelligent) software will just turn that directly into an IP address and use it. Some implementations of gethostbyname will detect the dotted format (and presumably the equivalent IPv6 format) and not do a looku...
How to get the first column of a pandas DataFrame as a Series?
...ataFrame({'x' : [1, 2, 3, 4], 'y' : [4, 5, 6, 7]})
>>> df
x y
0 1 4
1 2 5
2 3 6
3 4 7
>>> s = df.ix[:,0]
>>> type(s)
<class 'pandas.core.series.Series'>
>>>
===========================================================================
UPDATE
If...
Installing specific package versions with pip
...s here: http://pypi.python.org/pypi/MySQL-python/1.2.2
The download link 404s and the fallback URL links are re-directing infinitely due to sourceforge.net's recent upgrade and PyPI's stale URL.
So to properly install the driver, you can follow these steps:
pip uninstall MySQL_python
pip install ...
The modulo operation on negative numbers in Python
...nually fix it up by adding 7:
int result = (2 - N) % 7;
return result < 0 ? result + 7 : result;
(See http://en.wikipedia.org/wiki/Modulo_operator for how the sign of result is determined for different languages.)
share
...
Append value to empty vector in R?
...et.seed(21)
values <- sample(letters, 1e4, TRUE)
vector <- character(0)
# slow
system.time( for (i in 1:length(values)) vector[i] <- values[i] )
# user system elapsed
# 0.340 0.000 0.343
vector <- character(length(values))
# fast(er)
system.time( for (i in 1:length(values)) vec...
How to automatically generate N “distinct” colors?
...tness or saturation, you can distribute the hues like so:
// assumes hue [0, 360), saturation [0, 100), lightness [0, 100)
for(i = 0; i < 360; i += 360 / num_colors) {
HSLColor c;
c.hue = i;
c.saturation = 90 + randf() * 10;
c.lightness = 50 + randf() * 10;
addColor(c);
}
...
Standard deviation of a list
...
Since Python 3.4 / PEP450 there is a statistics module in the standard library, which has a method stdev for calculating the standard deviation of iterables like yours:
>>> A_rank = [0.8, 0.4, 1.2, 3.7, 2.6, 5.8]
>>> import statis...
plot a circle with pyplot
...
205
You need to add it to an axes. A Circle is a subclass of an Artist, and an axes has an add_arti...
How to nicely format floating numbers to String without unnecessary decimal 0?
...
407
If the idea is to print integers stored as doubles as if they are integers, and otherwise print...