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Get index of array element faster than O(n)
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answered Jun 5 '11 at 10:41
sawasawa
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What does Expression.Quote() do that Expression.Constant() can’t already do?
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5 Answers
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Active
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How do I get the picture size with PIL?
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513
from PIL import Image
im = Image.open('whatever.png')
width, height = im.size
According to ...
What is the purpose of setting a key in data.table?
...r adhoc-by.
## "cold" by
require(data.table)
DT <- data.table(x=rep(1:5, each=2), y=1:10)
DT[, mean(y), by=x] # no key is set, order of groups preserved in result
However, prior to v1.9.6, joins of the form x[i] required key to be set on x. With the new on= argument from v1.9.6+, this is not ...
Principal component analysis in Python
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ChristopheDChristopheD
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Check if all values of array are equal
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Mamun
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answered Feb 23 '16 at 4:34
golopotgolopot
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List comprehension in Ruby
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55
If you really want to, you can create an Array#comprehend method like this:
class Array
def ...
Find size of an array in Perl
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The predefined variable $[ specifies "The index of the first element in an array, and of the first character in a substring" (perldoc perlva...
How to convert array values to lowercase in PHP?
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358
use array_map():
$yourArray = array_map('strtolower', $yourArray);
In case you need to lower...
Unix shell script find out which directory the script file resides?
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591
In Bash, you should get what you need like this:
#!/usr/bin/env bash
BASEDIR=$(dirname "$0")...