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Select rows of a matrix that meet a condition
...can define a column by name:
m[m[, "three"] == 11,]
Or by number:
m[m[,3] == 11,]
Note that if only one row matches, the result is an integer vector, not a matrix.
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Does application.yml support environment variables?
...Dave Syer
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Differences between “java -cp” and “java -jar”?
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answered Aug 12 '12 at 13:59
Andreas DolkAndreas Dolk
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How do I iterate over a range of numbers defined by variables in Bash?
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for i in $(seq 1 $END); do echo $i; done
edit: I prefer seq over the other methods because I c...
How to check if a given directory exists in Ruby
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Totor
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answered Jul 6 '09 at 3:12
EmilyEmily
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Difference between single and double quotes in Bash
... echo '$(echo "upg")'
$(echo "upg")
The Bash manual has this to say:
3.1.2.2 Single Quotes
Enclosing characters in single quotes (') preserves the literal value of each character within the quotes. A single quote may not occur between single quotes, even when preceded by a backslash.
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How to get first element in a list of tuples?
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253
>>> a = [(1, u'abc'), (2, u'def')]
>>> [i[0] for i in a]
[1, 2]
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How can you represent inheritance in a database?
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@Bill Karwin describes three inheritance models in his SQL Antipatterns book, when proposing sol...
Having links relative to root?
...t was necessary for to use a specific base, for this I'll simply cite the W3's example:
For example, given the following BASE declaration and A declaration:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<HTML>
<HEAD>
<TIT...
what is the difference between a portlet and a servlet?
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answered Sep 26 '09 at 6:13
topcheftopchef
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