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How do multiple clients connect simultaneously to one port, say 80, on a server? [duplicate]
... don't get is how multiple clients can simultaneously connect to say port 80. I know each client has a unique (for their machine) port. Does the server reply back from an available port to the client, and simply state the reply came from 80? How does this work?
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How can I find the number of days between two Date objects in Ruby?
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How to check if hex color is “too black”?
...Int(c, 16); // convert rrggbb to decimal
var r = (rgb >> 16) & 0xff; // extract red
var g = (rgb >> 8) & 0xff; // extract green
var b = (rgb >> 0) & 0xff; // extract blue
var luma = 0.2126 * r + 0.7152 * g + 0.0722 * b; // per ITU-R BT.709
if (luma < 40) {
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How do you match only valid roman numerals with a regular expression?
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330
You can use the following regex for this:
^M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3...
Applying a function to every row of a table using dplyr?
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202
As of dplyr 0.2 (I think) rowwise() is implemented, so the answer to this problem becomes:
iri...
deleting rows in numpy array
... [7,8,9]])
To delete the first row, do this:
x = numpy.delete(x, (0), axis=0)
To delete the third column, do this:
x = numpy.delete(x,(2), axis=1)
So you could find the indices of the rows which have a 0 in them, put them in a list or a tuple and pass this as the second argument of the...
Normalizing mousewheel speed across browsers
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How do I base64 encode (decode) in C?
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106
Here's the one I'm using:
#include <stdint.h>
#include <stdlib.h>
static char en...
How to access the ith column of a NumPy multidimensional array?
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>>> test[:,0]
array([1, 3, 5])
Similarly,
>>> test[1,:]
array([3, 4])
lets you access rows. This is covered in Section 1.4 (Indexing) of the NumPy reference. This is quick, at least in my experience. It's certainly muc...
How to decide font color in white or black depending on background color?
...overall intensity of the color and choose the corresponding text.
if (red*0.299 + green*0.587 + blue*0.114) > 186 use #000000 else use #ffffff
The threshold of 186 is based on theory, but can be adjusted to taste. Based on the comments below a threshold of 150 may work better for you.
Edit: T...