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What do single quotes do in C++ when used on multiple characters?
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It's a multi-character literal. 1952805748 is 0x74657374, which decomposes as
0x74 -> 't'
0x65 -> 'e'
0x73 -> 's'
0x74 -> 't'
Edit:
C++ standard, §2.14.3/1 - Character literals
(...) An ordinary character literal that contains more than
one c-char...
How to combine multiple conditions to subset a data-frame using “OR”?
... it is to be handled as I intended, since ...
> NA & 1
[1] NA
> 0 & NA
[1] FALSE
Order of arguments may matter when using '&".
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How to atomically delete keys matching a pattern using Redis
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Starting with redis 2.6.0, you can run lua scripts, which execute atomically. I have never written one, but I think it would look something like this
EVAL "return redis.call('del', unpack(redis.call('keys', ARGV[1])))" 0 prefix:[YOUR_PREFIX e.g del...
How to sum up elements of a C++ vector?
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Actually there are quite a few methods.
int sum_of_elems = 0;
C++03
Classic for loop:
for(std::vector<int>::iterator it = vector.begin(); it != vector.end(); ++it)
sum_of_elems += *it;
Using a standard algorithm:
#include <numeric>
sum_of_elems = std::accu...
How do different retention policies affect my annotations?
...urce:
The old URL is dead now
hunter_meta and replaced with hunter-meta-2-098036. In case even this goes down, I am uploading the image of the page.
Image (Right Click and Select 'Open Image in New Tab/Window')
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Calculating how many minutes there are between two times
... you trying 'span.Minutes', this will return only the minutes of timespan [0~59], to return sum of all minutes from this interval, just use 'span.TotalMinutes'.
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PHP: How to generate a random, unique, alphanumeric string for use in a secret link?
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30 Answers
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How can I divide two integers to get a double?
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answered Mar 19 '09 at 4:14
NoahDNoahD
7,02244 gold badges2222 silver badges2828 bronze badges
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Return positions of a regex match() in Javascript?
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answered Feb 19 '10 at 10:49
GumboGumbo
572k100100 gold badges725725 silver badges804804 bronze badges
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How to split/partition a dataset into training and test datasets for, e.g., cross validation?
...k of the indices:
import numpy
# x is your dataset
x = numpy.random.rand(100, 5)
numpy.random.shuffle(x)
training, test = x[:80,:], x[80:,:]
or
import numpy
# x is your dataset
x = numpy.random.rand(100, 5)
indices = numpy.random.permutation(x.shape[0])
training_idx, test_idx = indices[:80], ind...