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What are the special dollar sign shell variables?
...ipeline exit status.
$! is the PID of the most recent background command.
$0 is the name of the shell or shell script.
Most of the above can be found under Special Parameters in the Bash Reference Manual. There are all the environment variables set by the shell.
For a comprehensive index, please ...
Android phone orientation overview including compass
...ow I think (hope) I have a better feeling for it again but I am still not 100%. I will try and explain my patchy understanding of it and hopefully people will be able to correct me if I am wrong in parts or fill in any blanks.
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What is the performance of Objects/Arrays in JavaScript? (specifically for Google V8)
...
+100
I created a test suite, precisely to explore these issues (and more) (archived copy).
And in that sense, you can see the performance...
How do I create test and train samples from one dataframe with pandas?
...ering how I would be able to split the dataframe into two random samples (80% and 20%) for training and testing.
23 Answers...
Show a number to two decimal places
...):
return number_format((float)$number, 2, '.', '');
Example:
$foo = "105";
echo number_format((float)$foo, 2, '.', ''); // Outputs -> 105.00
This function returns a string.
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improv...
stash@{1} is ambiguous?
I'm trying to get info about my stash, but git is telling me that stash@{0} and stash@{1} are ambiguous. git stash list works fine, and .git/logs/refs/stash seems to have the appropriate content (not that I'm an expert on git internals).
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Bash, no-arguments warning, and case decisions
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if [[ $# -eq 0 ]] ; then
echo 'some message'
exit 0
fi
case "$1" in
1) echo 'you gave 1' ;;
*) echo 'you gave something else' ;;
esac
The Advanced Bash-Scripting Guide is pretty good. In spite of its name, it does treat...
Transform DateTime into simple Date in Ruby on Rails
....to_date
NoMethodError: undefined method 'to_date' for #<DateTime: -1/2,0,2299161>
from (irb):1
>> require 'active_support/core_ext'
=> true
>> DateTime.new.to_date
=> Mon, 01 Jan -4712
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dplyr: “Error in n(): function should not be called directly”
...
120
I presume you have dplyr and plyr loaded in the same session. dplyr is not plyr. ddply is not a ...
Random alpha-numeric string in JavaScript? [duplicate]
...ring(length, chars) {
var result = '';
for (var i = length; i > 0; --i) result += chars[Math.floor(Math.random() * chars.length)];
return result;
}
var rString = randomString(32, '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ');
Here's a jsfiddle to demonstrate: htt...