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Why does Math.round(0.49999999999999994) return 1?
In the following program you can see that each value slightly less than .5 is rounded down, except for 0.5 .
5 Answers
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pandas: filter rows of DataFrame with operator chaining
...the boolean index.
In [96]: df
Out[96]:
A B C D
a 1 4 9 1
b 4 5 0 2
c 5 5 1 0
d 1 3 9 6
In [99]: df[(df.A == 1) & (df.D == 6)]
Out[99]:
A B C D
d 1 3 9 6
If you want to chain methods, you can add your own mask method and use that one.
In [90]: def mask(df, ke...
How to validate an Email in PHP?
How can I validate the input value is a valid email address using php5. Now I am using this code
7 Answers
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Using async/await for multiple tasks
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int[] ids = new[] { 1, 2, 3, 4, 5 };
Parallel.ForEach(ids, i => DoSomething(1, i, blogClien...
App Inventor 2 数学代码块 · App Inventor 2 中文网
...(abs)
返回给定数字的绝对值。如：-3.3 的绝对值是 3.3，5 的绝对值是 5，0 的绝对值是 0。
相反数 (neg)
返回给定数字的负数，若给定负数则返回正数。如：8 返回 -8，-0.7 返回 0.7，0 则仍然返回 0。
对数 (log)
返回给定数...
What is the bower (and npm) version syntax?
...
5 Answers
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Clojure 1.2.1/1.3/1.4 'proxy generated in Grails 2.0.0 runtime fails. 1.2.0 is fine
...03ca href=\"https://imgur.com/\"\u003e\u003csvg class=\"svg-icon\" width=\"50\" height=\"18\" viewBox=\"0 0 50 18\" fill=\"none\" xmlns=\"http://www.w3.org/2000/svg\"\u003e\u003cpath d=\"M46.1709 9.17788C46.1709 8.26454 46.2665 7.94324 47.1084 7.58816C47.4091 7.46349 47.7169 7.36433 48.0099 7.26993C...
Find indices of elements equal to zero in a NumPy array
...numpy.where() is my favorite.
>>> x = numpy.array([1,0,2,0,3,0,4,5,6,7,8])
>>> numpy.where(x == 0)[0]
array([1, 3, 5])
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How to test valid UUID/GUID?
... only accepts non-NIL UUIDs. Both of these solutions are for versions 1 to 5 (see the first character of the third block).
Therefore to validate a UUID...
/^[0-9a-f]{8}-[0-9a-f]{4}-[0-5][0-9a-f]{3}-[089ab][0-9a-f]{3}-[0-9a-f]{12}$/i
...ensures you have a canonically formatted UUID that is Versio...