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Finding the index of elements based on a condition using python list comprehension
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answered Sep 1 '11 at 13:20
Mike GrahamMike Graham
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Int division: Why is the result of 1/3 == 0?
...se returns the true result of division rounded towards zero. The result of 0.333... is thus rounded down to 0 here. (Note that the processor doesn't actually do any rounding, but you can think of it that way still.)
Also, note that if both operands (numbers) are given as floats; 3.0 and 1.0, or eve...
Is 1.0 a valid output from std::generate_canonical?
...o and one, without 1 , i.e. they are numbers from the half-open interval [0,1). The documention on cppreference.com of std::generate_canonical confirms this.
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How does Duff's device work?
...re's the Wikipedia example with some notations.
Let's say you're copying 20 bytes. The flow control of the program for the first pass is:
int count; // Set to 20
{
int n = (count + 7) / 8; // n is now 3. (The "while" is going
// ...
How to round up to the nearest 10 (or 100 or X)?
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If you just want to round up to the nearest power of 10, then just define:
roundUp <- function(x) 10^ceiling(log10(x))
This actually also works when x is a vector:
> roundUp(c(0.0023, 3.99, 10, 1003))
[1] 1e-02 1e+01 1e+01 1e+04
..but if you want to round to a "nice"...
Simple way to create matrix of random numbers
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Take a look at numpy.random.rand:
Docstring: rand(d0, d1, ..., dn)
Random values in a given shape.
Create an array of the given shape and propagate it with random
samples from a uniform distribution over [0, 1).
>>> import numpy as np
>>> np....
Types in MySQL: BigInt(20) vs Int(20)
...ous that they would allow for larger numbers; however, I can make an Int(20) or a BigInt(20) and that would make seem that it is not necessarily about size.
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mysql :: insert into table, data from another table?
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INSERT INTO action_2_members (campaign_id, mobile, vote, vote_date)
SELECT campaign_id, from_...
How can I get nth element from a list?
...re, the operator used is !!.
I.e. [1,2,3]!!1 gives you 2, since lists are 0-indexed.
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Checking if array is multidimensional or not?
...anywhere. If it has to be in the first item, you'd just do
is_array($arr[0]);
But, the most efficient general way I could find is to use a foreach loop on the array, shortcircuiting whenever a hit is found (at least the implicit loop is better than the straight for()):
$ more multi.php
<?php...