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Efficient way to determine number of digits in an integer
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107
Well, the most efficient way, presuming you know the size of the integer, would be a lookup. S...
pytest: assert almost equal
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I noticed that this question specifically asked about py.test. py.test 3.0 includes an approx() function (well, really class) that is very useful for this purpose.
import pytest
assert 2.2 == pytest.approx(2.3)
# fails, default is ± 2.3e-06
assert 2.2 == pytest.approx(2.3, 0.1)
# passes
# also...
Bitwise operation and usage
...bit at a time.
AND is 1 only if both of its inputs are 1, otherwise it's 0.
OR is 1 if one or both of its inputs are 1, otherwise it's 0.
XOR is 1 only if exactly one of its inputs are 1, otherwise it's 0.
NOT is 1 only if its input is 0, otherwise it's 0.
These can often be best shown as truth ...
Grid of responsive squares
... you can code :
HTML :
<div></div>
CSS
div {
width: 30%;
padding-bottom: 30%; /* = width for a square aspect ratio */
}
Here is a simple layout example of 3*3 squares grid using the code above.
With this technique, you can make any other aspect ratio, here is a table giv...
Grep characters before and after match?
... characters after
$> echo "some123_string_and_another" | grep -o -P '.{0,3}string.{0,4}'
23_string_and
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How to use hex color values
...f, green ff and blue ff. You can write hexadecimal notation in Swift using 0x prefix, e.g 0xFF
To simplify the conversion, let's create an initializer that takes integer (0 - 255) values:
extension UIColor {
convenience init(red: Int, green: Int, blue: Int) {
assert(red >= 0 &&...
Multiple aggregations of the same column using pandas GroupBy.agg()
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You can simply pass the functions as a list:
In [20]: df.groupby("dummy").agg({"returns": [np.mean, np.sum]})
Out[20]:
mean sum
dummy
1 0.036901 0.369012
or as a dictionary:
In [21]: df.groupby('dummy').agg({'returns':
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How do you convert epoch time in C#?
...ou convert Unix epoch time into real time in C#? (Epoch beginning 1/1/1970)
14 Answers
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Odd behavior when Java converts int to byte?
...mber is the positive version of that number
For example: 11111111 goes to 00000001 = -1. This is what Java will display as the value.
What you probably want to do is know the unsigned value of the byte.
You can accomplish this with a bitmask that deletes everything but the least significant 8 bit...
Generate array of all letters and digits
...g ruby, is it possible to make an array of each letter in the alphabet and 0-9 easily?
7 Answers
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