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Dynamic variable names in Bash
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@DeaDEnD -a declares an indexed array, not an associative array. Unless the argument to grep_search is a number, it will be treated as a parameter with a numeric value (which defaults to 0 if the parameter isn't set).
– chepner...
In Perl, how can I read an entire file into a string?
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I would do it like this:
my $file = "index.html";
my $document = do {
local $/ = undef;
open my $fh, "<", $file
or die "could not open $file: $!";
<$fh>;
};
Note the use of the three-argument version of open. It is much safer than ...
What does “Document-oriented” vs. Key-Value mean when talking about MongoDB vs Cassandra?
...s exactly what the name suggests: it's a storage system that stores values indexed by a key. You're limited to query by key and the values are opaque, the store doesn't know anything about them. This allows very fast read and write operations (a simple disk access) and I see this model as a kind of ...
How do I retrieve the number of columns in a Pandas data frame?
...the number of columns.
And for those who want the number of rows:
len(df.index)
For a tuple containing the number of both rows and columns:
df.shape
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How can I determine the current line number in JavaScript?
...e.stack.toString().split(/\r\n|\n/);
// We want our caller's frame. It's index into |stack| depends on the
// browser and browser version, so we need to search for the second frame:
var frameRE = /:(\d+):(?:\d+)[^\d]*$/;
do {
var frame = stack.shift();
} while (!frameRE.exec(frame) &am...
Can't update Macports (with Mac OS X Mavericks)
..."Command Line Tools for OS X Mavericks" from developer.apple.com/downloads/index.action# and install it.
– qazwsx
Apr 26 '14 at 17:24
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Rotating and spacing axis labels in ggplot2
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Change the last line to
q + theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1))
By default, the axes are aligned at the center of the text, even when rotated. When you rotate +/- 90 degrees, you usually want it to be aligned at th...
sqlalchemy: how to join several tables by one query?
... @PetrusTheron Like I said, query will yield 3-tuples. You can index elements, or just unpack: for (user, doc, perm) in query: print "Document: %s" % doc
– letitbee
Oct 15 '16 at 16:39
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How to remove old Docker containers
This question is related to Should I be concerned about excess, non-running, Docker containers? .
61 Answers
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Finding quaternion representing the rotation from one vector to another
I have two vectors u and v. Is there a way of finding a quaternion representing the rotation from u to v?
7 Answers
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